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8:35 p.m.

Hello
This is my first post, been lurking around for a while...
Been using Houdini for only a few months, so excuse the newbie tone of
this question...
I'm interested in using Houdini to create shapes of this sort
http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
What would be the way to go about creating, say, a Lituus shape? It
seems to me that the type of equation that is being used contains
symbols that I have never seen in Houdini, but I could be wrong.
Thanks!
Alex

8:53 p.m.

hey alex
take a look at this entry in the forum
http://forums.odforce.net/index.php?/topic/10718-isosurface-spiral-function
:)
On Tue, Mar 9, 2010 at 2:35 PM, Alex Czetwertynski <alex at franktheplumber.com

wrote:

Hello
This is my first post, been lurking around for a while...
Been using Houdini for only a few months, so excuse the newbie tone of
this question...
I'm interested in using Houdini to create shapes of this sort
http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
What would be the way to go about creating, say, a Lituus shape? It
seems to me that the type of equation that is being used contains
symbols that I have never seen in Houdini, but I could be wrong.
Thanks!
Alex
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Sidefx-houdini-list at sidefx.com
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--
brian
9:09 p.m.

Thanks Brian
I looked at the thread, but feel like I am still missing something.
In the case of the thread on ODforce, do you have to create variables
like "ff" and "bb" in advance?
Or with an equation such as "(-e^2) + 2*e^2*x + (1 - e^2)*x^2 + y^2 ==
0" where would you declare what "e" is?
Once again, sorry if this is an obvious one...
Alex
On Mar 8, 2010, at 5:53 PM, brian goodwin wrote:

hey alex
take a look at this entry in the forum
http://forums.odforce.net/index.php?/topic/10718-isosurface-spiral-function
:)
On Tue, Mar 9, 2010 at 2:35 PM, Alex Czetwertynski <alex at franktheplumber.com
> wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
brian
_______________________________________________
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Sidefx-houdini-list at sidefx.com
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9:16 p.m.

This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com> wrote:

Hello
This is my first post, been lurking around for a while...
Been using Houdini for only a few months, so excuse the newbie tone of
this question...
I'm interested in using Houdini to create shapes of this sort
http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
What would be the way to go about creating, say, a Lituus shape? ?It
seems to me that the type of equation that is being used contains
symbols that I have never seen in Houdini, but I could be wrong.
Thanks!
Alex
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
9:52 p.m.

Thanks Andrew
So pasting that into a textport produced the set of nodes I can see
listed in the code, but the end result is...all the points bunched up
at 0,0,0...
I can see we have a one column grid whose points are being modified in
the Point SOP Weight Attribute.
I think that this is potentially where the code is being
misinterpreted by Houdini as all I get in the Position Attribute for
$TX and $TY is a bezier() function.
Here is a screenshot of my parameter and network window.
http://plumbercloud.com/misc_public/Lituus.png
Thanks!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:

This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

12:05 a.m.

If you go a little further into that site you can see all the parametrizations are already
in there: e.g.
http://xahlee.org/SpecialPlaneCurves_dir/EpiHypocycloid_dir/epiHypocycloi...
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Tue, March 9, 2010 10:52:52 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
So pasting that into a textport produced the set of nodes I can see
listed in the code, but the end result is...all the points bunched up
at 0,0,0...
I can see we have a one column grid whose points are being modified in
the Point SOP Weight Attribute.
I think that this is potentially where the code is being
misinterpreted by Houdini as all I get in the Position Attribute for
$TX and $TY is a bezier() function.
Here is a screenshot of my parameter and network window.
http://plumbercloud.com/misc_public/Lituus.png
Thanks!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:

This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
11:38 a.m.

The line wrapping in the email formatting that I referred to probably
got you. Basically any line that doesn't begin with "op" or "ch"
belongs on the end of the previous line.
Cheers
On 8 March 2010 18:52, Alex Czetwertynski <alex at franktheplumber.com> wrote:

Thanks Andrew
So pasting that into a textport produced the set of nodes I can see
listed in the code, but the end result is...all the points bunched up
at 0,0,0...
I can see we have a one column grid whose points are being modified in
the Point SOP Weight Attribute.
I think that this is potentially where the code is being
misinterpreted by Houdini as all I get in the Position Attribute for
$TX and $TY is a bezier() function.
Here is a screenshot of my parameter and network window.
http://plumbercloud.com/misc_public/Lituus.png
Thanks!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
> This site is using mostly polar coordinates. Houdini uses mostly
> cartesian coordinates:
>
> http://en.wikipedia.org/wiki/Polar_coordinate_system
> http://en.wikipedia.org/wiki/Cartesian_coordinate_system
>
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
>
> In any case to model something like this in Houdini you to set up
> extra points to sample, and then do a conversion to cartesian as you
> go. Take a look at the point SOP in this network: (Drop this script in
> a textport in Houdini - watch out for line wrapping from the email:)
> ---------------------------------------------------------
>
> # Automatically generated script: Monday March 08, 18:11
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node Lituus (Object/geo)
> opadd -n geo Lituus
> oplocate -x 3.69 -y 0.286303 Lituus
> opset -S on Lituus
> opparm Lituus use_dcolor ( off )
> chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off Lituus
> opexprlanguage -s hscript Lituus
> opcf Lituus
>
> # Node file1 (Sop/file)
> opadd -n file file1
> oplocate -x 0 -y 0 file1
> opset -d off -r off file1
> opexprlanguage -s hscript file1
>
> # Node grid1 (Sop/grid)
> opadd -n grid grid1
> oplocate -x 11.8336 -y 5.95065 grid1
> opparm grid1 rows ( 100 ) cols ( 1 )
> opexprlanguage -s hscript grid1
>
> # Node point1 (Sop/point)
> opadd -n point point1
> oplocate -x 11.8668 -y 4.82124 point1
> opparm point1 ?numcustom ( 1 )
> chblockbegin
> chadd -t 0 0 point1 tx
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a ?-F 'cos(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tx
> chadd -t 0 0 point1 ty
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a ?-F '$TY' point1/ty
> chadd -t 0 0 point1 weight
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a ?-F '$PI *($PT/18)*90' point1/
> weight
> chadd -t 0 0 point1 tz
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a ?-F 'sin(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tz
> chblockend
> opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
> opset -d off -r off point1
> opexprlanguage -s hscript point1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 11.8668 -y 3.86161 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a ?-F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) pattern ( 0 )
> opset -d off -r off delete1
> opexprlanguage -s hscript delete1
>
> # Node null1 (Sop/null)
> opadd -n null null1
> oplocate -x 11.8668 -y 2.98478 null1
> opset -d on -r on ?null1
> opexprlanguage -s hscript null1
> oporder -e file1 grid1 point1 delete1 null1
> opcf ..
>
> opcf /obj
> opcf Lituus
> opwire -n grid1 -0 point1
> opwire -n point1 -0 delete1
> opwire -n delete1 -0 null1
> opcf ..
> opcf $saved_path
>
> ---------------------------------------------------------
>
>
> Cheers
>
>
> On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
> wrote:
>
>> Hello
>>
>> This is my first post, been lurking around for a while...
>> Been using Houdini for only a few months, so excuse the newbie tone
>> of
>> this question...
>>
>> I'm interested in using Houdini to create shapes of this sort
>> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>>
>> What would be the way to go about creating, say, a Lituus shape? ?It
>> seems to me that the type of equation that is being used contains
>> symbols that I have never seen in Houdini, but I could be wrong.
>>
>> Thanks!
>> Alex
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
3:14 p.m.

Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:

This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

5:02 a.m.

Hi Alex,
The Iso Surface surface node generates an isometric surface from an implicit function. So
you don't necessarily have to go back to trig and parametrize, actually there are a
lot of parametrizations already done out there on the web. Check out these guys:
http://www.freigeist.cc/gallery.html
http://www.oliverlabs.net/view.php?menuitem=160
http://www.algebraicsurface.net/
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

5:26 a.m.

Alex,
BTW, in the isosurface node those algebraic surfaces should go something like this:
e.g. the Calyx, x2+y2z3 = z4 becomes $X*$X+$Y*$Y*$Z*$Z*$Z - $Z*$Z*$Z*$Z. Just enter it
into the implicit function parameter window and you're done. No trig required hehe.
Your (y4 - x4 + a y2 + b x2 = 0) would just need some numbers of your choosing plugged in
for a and b.
best,
david
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
This site is using mostly polar coordinates. Houdini uses mostly
cartesian coordinates:
http://en.wikipedia.org/wiki/Polar_coordinate_system
http://en.wikipedia.org/wiki/Cartesian_coordinate_system
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
In any case to model something like this in Houdini you to set up
extra points to sample, and then do a conversion to cartesian as you
go. Take a look at the point SOP in this network: (Drop this script in
a textport in Houdini - watch out for line wrapping from the email:)
---------------------------------------------------------
# Automatically generated script: Monday March 08, 18:11
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node Lituus (Object/geo)
opadd -n geo Lituus
oplocate -x 3.69 -y 0.286303 Lituus
opset -S on Lituus
opparm Lituus use_dcolor ( off )
chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
opset -d on -r off Lituus
opexprlanguage -s hscript Lituus
opcf Lituus
# Node file1 (Sop/file)
opadd -n file file1
oplocate -x 0 -y 0 file1
opset -d off -r off file1
opexprlanguage -s hscript file1
# Node grid1 (Sop/grid)
opadd -n grid grid1
oplocate -x 11.8336 -y 5.95065 grid1
opparm grid1 rows ( 100 ) cols ( 1 )
opexprlanguage -s hscript grid1
# Node point1 (Sop/point)
opadd -n point point1
oplocate -x 11.8668 -y 4.82124 point1
opparm point1 numcustom ( 1 )
chblockbegin
chadd -t 0 0 point1 tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
1/sqrt(ch("weight"))' point1/tx
chadd -t 0 0 point1 ty
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
chadd -t 0 0 point1 weight
chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
weight
chadd -t 0 0 point1 tz
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
1/sqrt(ch("weight"))' point1/tz
chblockend
opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
opset -d off -r off point1
opexprlanguage -s hscript point1
# Node delete1 (Sop/delete)
opadd -n delete delete1
oplocate -x 11.8668 -y 3.86161 delete1
chblockbegin
chadd -t 0 0 delete1 rangeend
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
chblockend
opparm delete1 entity ( point ) pattern ( 0 )
opset -d off -r off delete1
opexprlanguage -s hscript delete1
# Node null1 (Sop/null)
opadd -n null null1
oplocate -x 11.8668 -y 2.98478 null1
opset -d on -r on null1
opexprlanguage -s hscript null1
oporder -e file1 grid1 point1 delete1 null1
opcf ..
opcf /obj
opcf Lituus
opwire -n grid1 -0 point1
opwire -n point1 -0 delete1
opwire -n delete1 -0 null1
opcf ..
opcf $saved_path
---------------------------------------------------------
Cheers
On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
wrote:
> Hello
>
> This is my first post, been lurking around for a while...
> Been using Houdini for only a few months, so excuse the newbie tone
> of
> this question...
>
> I'm interested in using Houdini to create shapes of this sort
> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>
> What would be the way to go about creating, say, a Lituus shape? It
> seems to me that the type of equation that is being used contains
> symbols that I have never seen in Houdini, but I could be wrong.
>
> Thanks!
> Alex
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

noon

Thanks David
That is an awesome explanation! I can now generate all of those shapes!
If you wouldn't mind explaining one more thing....In this case, why
did the equal sign in the original equation become a minus in the
implicit function?
Thanks again, this is really fun
Alex
On Mar 10, 2010, at 2:26 AM, David McBride wrote:

Alex,
BTW, in the isosurface node those algebraic surfaces should go
something like this:
e.g. the Calyx, x2+y2z3 = z4 becomes $X*$X+$Y*$Y*$Z*$Z*$Z - $Z*
$Z*$Z*$Z. Just enter it into the implicit function parameter window
and you're done. No trig required hehe. Your (y4 - x4 + a y2 + b x2
= 0) would just need some numbers of your choosing plugged in for a
and b.
best,
david
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
> This site is using mostly polar coordinates. Houdini uses mostly
> cartesian coordinates:
>
> http://en.wikipedia.org/wiki/Polar_coordinate_system
> http://en.wikipedia.org/wiki/Cartesian_coordinate_system
>
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
>
> In any case to model something like this in Houdini you to set up
> extra points to sample, and then do a conversion to cartesian as you
> go. Take a look at the point SOP in this network: (Drop this script
> in
> a textport in Houdini - watch out for line wrapping from the email:)
> ---------------------------------------------------------
>
> # Automatically generated script: Monday March 08, 18:11
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node Lituus (Object/geo)
> opadd -n geo Lituus
> oplocate -x 3.69 -y 0.286303 Lituus
> opset -S on Lituus
> opparm Lituus use_dcolor ( off )
> chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off Lituus
> opexprlanguage -s hscript Lituus
> opcf Lituus
>
> # Node file1 (Sop/file)
> opadd -n file file1
> oplocate -x 0 -y 0 file1
> opset -d off -r off file1
> opexprlanguage -s hscript file1
>
> # Node grid1 (Sop/grid)
> opadd -n grid grid1
> oplocate -x 11.8336 -y 5.95065 grid1
> opparm grid1 rows ( 100 ) cols ( 1 )
> opexprlanguage -s hscript grid1
>
> # Node point1 (Sop/point)
> opadd -n point point1
> oplocate -x 11.8668 -y 4.82124 point1
> opparm point1 numcustom ( 1 )
> chblockbegin
> chadd -t 0 0 point1 tx
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tx
> chadd -t 0 0 point1 ty
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
> chadd -t 0 0 point1 weight
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
> weight
> chadd -t 0 0 point1 tz
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tz
> chblockend
> opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
> opset -d off -r off point1
> opexprlanguage -s hscript point1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 11.8668 -y 3.86161 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) pattern ( 0 )
> opset -d off -r off delete1
> opexprlanguage -s hscript delete1
>
> # Node null1 (Sop/null)
> opadd -n null null1
> oplocate -x 11.8668 -y 2.98478 null1
> opset -d on -r on null1
> opexprlanguage -s hscript null1
> oporder -e file1 grid1 point1 delete1 null1
> opcf ..
>
> opcf /obj
> opcf Lituus
> opwire -n grid1 -0 point1
> opwire -n point1 -0 delete1
> opwire -n delete1 -0 null1
> opcf ..
> opcf $saved_path
>
> ---------------------------------------------------------
>
>
> Cheers
>
>
> On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
> wrote:
>
>> Hello
>>
>> This is my first post, been lurking around for a while...
>> Been using Houdini for only a few months, so excuse the newbie tone
>> of
>> this question...
>>
>> I'm interested in using Houdini to create shapes of this sort
>> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>>
>> What would be the way to go about creating, say, a Lituus shape? It
>> seems to me that the type of equation that is being used contains
>> symbols that I have never seen in Houdini, but I could be wrong.
>>
>> Thanks!
>> Alex
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

6:52 p.m.

it starts off with z^4 on the right. i subtracted z^4 from both sides. the node likes
f=0
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Thu, March 11, 2010 1:00:11 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks David
That is an awesome explanation! I can now generate all of those shapes!
If you wouldn't mind explaining one more thing....In this case, why
did the equal sign in the original equation become a minus in the
implicit function?
Thanks again, this is really fun
Alex
On Mar 10, 2010, at 2:26 AM, David McBride wrote:

Alex,
BTW, in the isosurface node those algebraic surfaces should go
something like this:
e.g. the Calyx, x2+y2z3 = z4 becomes $X*$X+$Y*$Y*$Z*$Z*$Z - $Z*
$Z*$Z*$Z. Just enter it into the implicit function parameter window
and you're done. No trig required hehe. Your (y4 - x4 + a y2 + b x2
= 0) would just need some numbers of your choosing plugged in for a
and b.
best,
david
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
> This site is using mostly polar coordinates. Houdini uses mostly
> cartesian coordinates:
>
> http://en.wikipedia.org/wiki/Polar_coordinate_system
> http://en.wikipedia.org/wiki/Cartesian_coordinate_system
>
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
>
> In any case to model something like this in Houdini you to set up
> extra points to sample, and then do a conversion to cartesian as you
> go. Take a look at the point SOP in this network: (Drop this script
> in
> a textport in Houdini - watch out for line wrapping from the email:)
> ---------------------------------------------------------
>
> # Automatically generated script: Monday March 08, 18:11
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node Lituus (Object/geo)
> opadd -n geo Lituus
> oplocate -x 3.69 -y 0.286303 Lituus
> opset -S on Lituus
> opparm Lituus use_dcolor ( off )
> chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off Lituus
> opexprlanguage -s hscript Lituus
> opcf Lituus
>
> # Node file1 (Sop/file)
> opadd -n file file1
> oplocate -x 0 -y 0 file1
> opset -d off -r off file1
> opexprlanguage -s hscript file1
>
> # Node grid1 (Sop/grid)
> opadd -n grid grid1
> oplocate -x 11.8336 -y 5.95065 grid1
> opparm grid1 rows ( 100 ) cols ( 1 )
> opexprlanguage -s hscript grid1
>
> # Node point1 (Sop/point)
> opadd -n point point1
> oplocate -x 11.8668 -y 4.82124 point1
> opparm point1 numcustom ( 1 )
> chblockbegin
> chadd -t 0 0 point1 tx
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tx
> chadd -t 0 0 point1 ty
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
> chadd -t 0 0 point1 weight
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
> weight
> chadd -t 0 0 point1 tz
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tz
> chblockend
> opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
> opset -d off -r off point1
> opexprlanguage -s hscript point1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 11.8668 -y 3.86161 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) pattern ( 0 )
> opset -d off -r off delete1
> opexprlanguage -s hscript delete1
>
> # Node null1 (Sop/null)
> opadd -n null null1
> oplocate -x 11.8668 -y 2.98478 null1
> opset -d on -r on null1
> opexprlanguage -s hscript null1
> oporder -e file1 grid1 point1 delete1 null1
> opcf ..
>
> opcf /obj
> opcf Lituus
> opwire -n grid1 -0 point1
> opwire -n point1 -0 delete1
> opwire -n delete1 -0 null1
> opcf ..
> opcf $saved_path
>
> ---------------------------------------------------------
>
>
> Cheers
>
>
> On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
> wrote:
>
>> Hello
>>
>> This is my first post, been lurking around for a while...
>> Been using Houdini for only a few months, so excuse the newbie tone
>> of
>> this question...
>>
>> I'm interested in using Houdini to create shapes of this sort
>> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>>
>> What would be the way to go about creating, say, a Lituus shape? It
>> seems to me that the type of equation that is being used contains
>> symbols that I have never seen in Houdini, but I could be wrong.
>>
>> Thanks!
>> Alex
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

_______________________________________________
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Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
12:04 p.m.

Oh and one more question...
In an equation such as 6x2 - 2x4 = y2z2
Are the numbers 6 and 4 supposed to multiply the following numbers or
add to them?
Thanks again
Alex
On Mar 10, 2010, at 2:26 AM, David McBride wrote:

Alex,
BTW, in the isosurface node those algebraic surfaces should go
something like this:
e.g. the Calyx, x2+y2z3 = z4 becomes $X*$X+$Y*$Y*$Z*$Z*$Z - $Z*
$Z*$Z*$Z. Just enter it into the implicit function parameter window
and you're done. No trig required hehe. Your (y4 - x4 + a y2 + b x2
= 0) would just need some numbers of your choosing plugged in for a
and b.
best,
david
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
> This site is using mostly polar coordinates. Houdini uses mostly
> cartesian coordinates:
>
> http://en.wikipedia.org/wiki/Polar_coordinate_system
> http://en.wikipedia.org/wiki/Cartesian_coordinate_system
>
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
>
> In any case to model something like this in Houdini you to set up
> extra points to sample, and then do a conversion to cartesian as you
> go. Take a look at the point SOP in this network: (Drop this script
> in
> a textport in Houdini - watch out for line wrapping from the email:)
> ---------------------------------------------------------
>
> # Automatically generated script: Monday March 08, 18:11
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node Lituus (Object/geo)
> opadd -n geo Lituus
> oplocate -x 3.69 -y 0.286303 Lituus
> opset -S on Lituus
> opparm Lituus use_dcolor ( off )
> chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off Lituus
> opexprlanguage -s hscript Lituus
> opcf Lituus
>
> # Node file1 (Sop/file)
> opadd -n file file1
> oplocate -x 0 -y 0 file1
> opset -d off -r off file1
> opexprlanguage -s hscript file1
>
> # Node grid1 (Sop/grid)
> opadd -n grid grid1
> oplocate -x 11.8336 -y 5.95065 grid1
> opparm grid1 rows ( 100 ) cols ( 1 )
> opexprlanguage -s hscript grid1
>
> # Node point1 (Sop/point)
> opadd -n point point1
> oplocate -x 11.8668 -y 4.82124 point1
> opparm point1 numcustom ( 1 )
> chblockbegin
> chadd -t 0 0 point1 tx
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tx
> chadd -t 0 0 point1 ty
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
> chadd -t 0 0 point1 weight
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
> weight
> chadd -t 0 0 point1 tz
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tz
> chblockend
> opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
> opset -d off -r off point1
> opexprlanguage -s hscript point1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 11.8668 -y 3.86161 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) pattern ( 0 )
> opset -d off -r off delete1
> opexprlanguage -s hscript delete1
>
> # Node null1 (Sop/null)
> opadd -n null null1
> oplocate -x 11.8668 -y 2.98478 null1
> opset -d on -r on null1
> opexprlanguage -s hscript null1
> oporder -e file1 grid1 point1 delete1 null1
> opcf ..
>
> opcf /obj
> opcf Lituus
> opwire -n grid1 -0 point1
> opwire -n point1 -0 delete1
> opwire -n delete1 -0 null1
> opcf ..
> opcf $saved_path
>
> ---------------------------------------------------------
>
>
> Cheers
>
>
> On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
> wrote:
>
>> Hello
>>
>> This is my first post, been lurking around for a while...
>> Been using Houdini for only a few months, so excuse the newbie tone
>> of
>> this question...
>>
>> I'm interested in using Houdini to create shapes of this sort
>> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>>
>> What would be the way to go about creating, say, a Lituus shape? It
>> seems to me that the type of equation that is being used contains
>> symbols that I have never seen in Houdini, but I could be wrong.
>>
>> Thanks!
>> Alex
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

6:43 p.m.

I think they mean 6x^2-2x^4=y^2z^2.
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Thu, March 11, 2010 1:04:06 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Oh and one more question...
In an equation such as 6x2 - 2x4 = y2z2
Are the numbers 6 and 4 supposed to multiply the following numbers or
add to them?
Thanks again
Alex
On Mar 10, 2010, at 2:26 AM, David McBride wrote:
Alex,
BTW, in the isosurface node those algebraic surfaces should go
something like this:
e.g. the Calyx, x2+y2z3 = z4 becomes $X*$X+$Y*$Y*$Z*$Z*$Z - $Z*
$Z*$Z*$Z. Just enter it into the implicit function parameter window
and you're done. No trig required hehe. Your (y4 - x4 + a y2 + b x2
= 0) would just need some numbers of your choosing plugged in for a
and b.
best,
david
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Wed, March 10, 2010 4:14:42 AM
Subject: Re: [Sidefx-houdini-list] First question to the list
Thanks Andrew
I was not able to get the formatting right, even by copy pasting into
a text editor (I'm on a mac...), but I just recreated the network
based and it worked fine.
My knowledge of mathematics is probably too basic to understand
exactly what is going on, as I was trying to figure out how I could
plug the following cartesian equation
(y4 - x4 + a y2 + b x2 = 0)
into a similar setup, but have to admit I have no idea. Will go back
to Trig 101 before I keep asking questions about this....
Thanks for your help, at least I now have a nice Lituus curve!
Alex
On Mar 8, 2010, at 6:16 PM, Andrew D Lyons wrote:
> This site is using mostly polar coordinates. Houdini uses mostly
> cartesian coordinates:
>
> http://en.wikipedia.org/wiki/Polar_coordinate_system
> http://en.wikipedia.org/wiki/Cartesian_coordinate_system
>
http://en.wikipedia.org/wiki/Polar_coordinate_system#Converting_between_p...
>
> In any case to model something like this in Houdini you to set up
> extra points to sample, and then do a conversion to cartesian as you
> go. Take a look at the point SOP in this network: (Drop this script
> in
> a textport in Houdini - watch out for line wrapping from the email:)
> ---------------------------------------------------------
>
> # Automatically generated script: Monday March 08, 18:11
> \set noalias = 1
> set saved_path = `execute("oppwf")`
> opcf /obj
>
> # Node Lituus (Object/geo)
> opadd -n geo Lituus
> oplocate -x 3.69 -y 0.286303 Lituus
> opset -S on Lituus
> opparm Lituus use_dcolor ( off )
> chautoscope Lituus +tx +ty +tz +rx +ry +rz +sx +sy +sz
> opset -d on -r off Lituus
> opexprlanguage -s hscript Lituus
> opcf Lituus
>
> # Node file1 (Sop/file)
> opadd -n file file1
> oplocate -x 0 -y 0 file1
> opset -d off -r off file1
> opexprlanguage -s hscript file1
>
> # Node grid1 (Sop/grid)
> opadd -n grid grid1
> oplocate -x 11.8336 -y 5.95065 grid1
> opparm grid1 rows ( 100 ) cols ( 1 )
> opexprlanguage -s hscript grid1
>
> # Node point1 (Sop/point)
> opadd -n point point1
> oplocate -x 11.8668 -y 4.82124 point1
> opparm point1 numcustom ( 1 )
> chblockbegin
> chadd -t 0 0 point1 tx
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tx
> chadd -t 0 0 point1 ty
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$TY' point1/ty
> chadd -t 0 0 point1 weight
> chkey -t 0 -v 1 -m 0 -a 0 -A 0 -T a -F '$PI *($PT/18)*90' point1/
> weight
> chadd -t 0 0 point1 tz
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin(ch("weight"))*
> 1/sqrt(ch("weight"))' point1/tz
> chblockend
> opparm point1 t ( tx ty tz ) doweight ( on ) weight ( weight )
> opset -d off -r off point1
> opexprlanguage -s hscript point1
>
> # Node delete1 (Sop/delete)
> opadd -n delete delete1
> oplocate -x 11.8668 -y 3.86161 delete1
> chblockbegin
> chadd -t 0 0 delete1 rangeend
> chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F '$N' delete1/rangeend
> chblockend
> opparm delete1 entity ( point ) pattern ( 0 )
> opset -d off -r off delete1
> opexprlanguage -s hscript delete1
>
> # Node null1 (Sop/null)
> opadd -n null null1
> oplocate -x 11.8668 -y 2.98478 null1
> opset -d on -r on null1
> opexprlanguage -s hscript null1
> oporder -e file1 grid1 point1 delete1 null1
> opcf ..
>
> opcf /obj
> opcf Lituus
> opwire -n grid1 -0 point1
> opwire -n point1 -0 delete1
> opwire -n delete1 -0 null1
> opcf ..
> opcf $saved_path
>
> ---------------------------------------------------------
>
>
> Cheers
>
>
> On 8 March 2010 17:35, Alex Czetwertynski <alex at franktheplumber.com>
> wrote:
>
>> Hello
>>
>> This is my first post, been lurking around for a while...
>> Been using Houdini for only a few months, so excuse the newbie tone
>> of
>> this question...
>>
>> I'm interested in using Houdini to create shapes of this sort
>> http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
>>
>> What would be the way to go about creating, say, a Lituus shape? It
>> seems to me that the type of equation that is being used contains
>> symbols that I have never seen in Houdini, but I could be wrong.
>>
>> Thanks!
>> Alex
>> _______________________________________________
>> Sidefx-houdini-list mailing list
>> Sidefx-houdini-list at sidefx.com
>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>>
>
>
>
> --
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

5:39 a.m.

This was fun, glad you brought it up.
To see (y4 - x4 + a y2 + b x2 = 0) drop in a geometry node, go in and delete the file node
and add an isosurface node. Enter $Y*$Y*$Y*$Y-$X*$X*$X*$X+sin($FF)*$Y*$Y+cos($FF)*$X*$X
into the implicit function parameter window and hit the play button.
best,
david

8:06 a.m.

New subject: First question to the list(silly me ^ is ok for powers)

i thought ^ was reserved for exclusions in light masks etc. i just tried it and it works
for powers in the isosurface node. cool even simpler.
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

11:47 p.m.

Here you go. All you need in a short power point presentation:
http://www.google.com/url?sa=t&source=web&ct=res&cd=1&ved...
________________________________
From: Alex Czetwertynski <alex at franktheplumber.com>
To: sidefx-houdini-list at sidefx.com
Sent: Tue, March 9, 2010 9:35:04 AM
Subject: [Sidefx-houdini-list] First question to the list
Hello
This is my first post, been lurking around for a while...
Been using Houdini for only a few months, so excuse the newbie tone of
this question...
I'm interested in using Houdini to create shapes of this sort
http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
What would be the way to go about creating, say, a Lituus shape? It
seems to me that the type of equation that is being used contains
symbols that I have never seen in Houdini, but I could be wrong.
Thanks!
Alex
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

9:22 a.m.

Alex Czetwertynski wrote:

I'm interested in using Houdini to create shapes of this sort
http://xahlee.org/SpecialPlaneCurves_dir/specialPlaneCurves.html
What would be the way to go about creating, say, a Lituus shape? It
seems to me that the type of equation that is being used contains
symbols that I have never seen in Houdini, but I could be wrong.

It's just a simple matter of adjusting the equation for the Spiral
example from the Expression Cookbook in the documentation:
http://www.sidefx.com/docs/houdini10.0/ref/expression_cookbook
Regards,
-Edward
Drop this script in a textport in Houdini - watch out for line wrapping
from the email:
---------------------------------------------------------
# Automatically generated script: Tuesday March 09, 09:16
\set noalias = 1
set saved_path = `execute("oppwf")`
opcf /obj
# Node geo1 (Object/geo)
opadd geo geo1
opcf geo1
oprm file1
# Node line1 (Sop/line)
opadd line line1
oplocate -x -1.22941 -y 1.43529 line1
opparm line1 dir ( 1 0 0 ) points ( 3000 )
# Node point1 (Sop/point)
opadd point point1
oplocate -x -1.22941 -y 0.423529 point1
chblockbegin
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'cos($PT) * (1.0/sqrt($PT+1))'
point1/tx
chkey -t 0 -v 0 -m 0 -a 0 -A 0 -T a -F 'sin($PT) * (1.0/sqrt($PT+1))'
point1/tz
chblockend
# Node xform1 (Sop/xform)
opadd xform xform1
oplocate -x -1.22941 -y -0.564706 xform1
opparm xform1 scale ( 10 )
opset -d on xform1
opwire -n line1 -0 point1
opwire -n point1 -0 xform1
opcf ..
opcf $saved_path
---------------------------------------------------------
3:32 p.m.

New subject: 3D books including Houdini Manual Set

HI,
I am moving and need to lighten my load...
I have gathered up a bunch of 3D books over the past 13 years
including what was probably the last printed Houdini Manual Set
(Houdini 5, the 2 big purple boxes). Of course several of them are
outdated but include some oldies but goodies from Siggraph and the
like. (Have a Maya 3 Printed Manual Set too, 2 Black boxes)
I'd like to find some good homes and thought I'd reach out here
before just putting on Amazon. I posted the library to: http://
web.me.com/dreston/deliciouslibrary/index.html
If you have a look and see something your interested in, please just
email me off the list.
I really appreciate it. Sorry to spam the list.
Doug
dreston at mac.com