I've had this type of problem on and off for a while now, but its reared its ugly head again today. I'm still on H11.1.388.
quick scene
sphere and cube
sphere is static rbd with “deforming” transform, basically animating the transform inside at the sop level (to mimic a geo cached object)
cube is regular active rbd object
sphere is animated to collide with cube.
when I run this sim with “use deforming geometry” turned on on the sphere, I do not get any collision happening. Its like the deforming geo is not getting created properly at the start frame or something and its not intialized so it does not collide at all.
if I were to move the animation to the transform level of the sphere instead and turn off use deforming geo, it collides just fine.
I'm not sure whats going on, but it seems bug-like.
has anybody come across this before and knows of a solution?
I've tried all forms of creation frame settings.. and at one point yesterday I got it to work properly and if I didn't quit the scene file it seemed to keep working from that point forward but today when I quit/reloaded the file it stopped working again.
any ideas?
-johnc
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Technical Discussion » rbd with deforming geom not working
- redpaw
- 75 posts
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Houdini Lounge » anybody with alembic success?
- redpaw
- 75 posts
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New version of houdini somewhat fixes the problem, my simple sliding box
alembic file works,
however when I try to load some other meshes from maya, I am still getting errors, this time though, they are from the namespace that maya is exporting (which we can't avoid in our referencing pipeline)
I have objects with names like nameSpacebjectName and it seems that the python interpeter that is extracting the names from the alembic file is throwing up on the colon in the object name.
Can we have support for this type of object name? its not going to be an option to just not use names like that..because thats what maya exports
and a lot of companies use namespaces to keep things sane.
I think its probably just a matter of better string parsing is needed..
anybody else seeing this problem?
thanks in advance
-johnc
alembic file works,
however when I try to load some other meshes from maya, I am still getting errors, this time though, they are from the namespace that maya is exporting (which we can't avoid in our referencing pipeline)
I have objects with names like nameSpacebjectName and it seems that the python interpeter that is extracting the names from the alembic file is throwing up on the colon in the object name.
Can we have support for this type of object name? its not going to be an option to just not use names like that..because thats what maya exports
and a lot of companies use namespaces to keep things sane.
I think its probably just a matter of better string parsing is needed..
anybody else seeing this problem?
thanks in advance
-johnc
Houdini Lounge » anybody with alembic success?
- redpaw
- 75 posts
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I just installed the latest 11.1.22 and cannot get any sort of alembic cache imported at all.. the files are coming from maya reference plugin, and we've tried to dumb down the files to as simple of a file as possible
single deforming sphere
we're getting a python error
file “<stdin>” line 1 in <module>
file “opdefObject/alembicarchive?PythonModule”. line 16 in BuildHeirarchyRoot
file “opdefObject/alembicarchive?PythonModule”. line 70 in walkHeirarchy
file “opdefObject/alembicarchive?PythonModule”. line 27 in ExpressionToParm
AttributeError ‘module’ object has no attribute ‘relpath’
any ideas?
thanks
-johnc
single deforming sphere
we're getting a python error
file “<stdin>” line 1 in <module>
file “opdefObject/alembicarchive?PythonModule”. line 16 in BuildHeirarchyRoot
file “opdefObject/alembicarchive?PythonModule”. line 70 in walkHeirarchy
file “opdefObject/alembicarchive?PythonModule”. line 27 in ExpressionToParm
AttributeError ‘module’ object has no attribute ‘relpath’
any ideas?
thanks
-johnc
Technical Discussion » Question with writing the "moment" frame into attr
- redpaw
- 75 posts
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I've been trying to do something like this as well, chops sort of worked for me using triggers and such, but I've found that the “animated” vs “static” mode in chops is still a bit nebulous for doing this sort of thing.
My main issue is that “animated” seems to be way too slow to be usefull for any sort of point based switching on geo that has even a reasonable number of points. Its trying to make a separate channel for each point and that is resulting in a huge amount of data obviously.
if anyone has any good examples of this method using the faster “Static” settings, that would be awesome
-johnc
My main issue is that “animated” seems to be way too slow to be usefull for any sort of point based switching on geo that has even a reasonable number of points. Its trying to make a separate channel for each point and that is resulting in a huge amount of data obviously.
if anyone has any good examples of this method using the faster “Static” settings, that would be awesome
-johnc
Technical Discussion » Shatter with metaballs magnet fields
- redpaw
- 75 posts
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Is there a way to keep the shattering with metaball/magnet in the
DOPs automatic voroni fracturing system from “exploding” on a per metaball or per magnet field basis.
It seems that If I place a magnet field with a metaball inside of an RBD object, it wants to radially explode. out from the center of that metaball.
The metaballs are scaling up on a single frame to cover over areas I want to shatter. I'm not sure if its this scale anim or the nature of the voroni fracture system thats making them explode outward, but the only way I can dial it down is on the voroni fracture configure node itself, and that seems to be kinda clunky if I also want to use it to collide pieces with the floor later on in the sim.
can anyone enlighten me as to how the system is actually wired up internally, I can't seem to find the nodes that its sourcing the velocity for metaball / magnet “collisions” from ?
thanks in advance
-johnc
DOPs automatic voroni fracturing system from “exploding” on a per metaball or per magnet field basis.
It seems that If I place a magnet field with a metaball inside of an RBD object, it wants to radially explode. out from the center of that metaball.
The metaballs are scaling up on a single frame to cover over areas I want to shatter. I'm not sure if its this scale anim or the nature of the voroni fracture system thats making them explode outward, but the only way I can dial it down is on the voroni fracture configure node itself, and that seems to be kinda clunky if I also want to use it to collide pieces with the floor later on in the sim.
can anyone enlighten me as to how the system is actually wired up internally, I can't seem to find the nodes that its sourcing the velocity for metaball / magnet “collisions” from ?
thanks in advance
-johnc
Technical Discussion » keeping track of the "age" of a point
- redpaw
- 75 posts
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Is there a way to tag a point with its “age” in frames?
There is a count chop
what I have is a shattering piece of geometry,
I would like to track the “age” of the new shattered pieces
shouldn't I be able to hook up an attribute to the geo that
when an object shatters in dops its “age” is created as 0 and then use a chop network to increment a count on that object each frame?
I tried a simple version of this and it didn't seem to do anything I expected.
I've still got a lot to learn about chops..
thanks in advance
-johnc
There is a count chop
what I have is a shattering piece of geometry,
I would like to track the “age” of the new shattered pieces
shouldn't I be able to hook up an attribute to the geo that
when an object shatters in dops its “age” is created as 0 and then use a chop network to increment a count on that object each frame?
I tried a simple version of this and it didn't seem to do anything I expected.
I've still got a lot to learn about chops..
thanks in advance
-johnc
Technical Discussion » create 'spider web' fracturing shape
- redpaw
- 75 posts
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try this I used it recently and it works pretty well.
make a couple of circles with a limited number of points. say 5 or 7
overlap them slightly and align them to the surface you want to shatter.
pipe their points into the points input of the voroni shatter sop.
and run the shatter.
you should get a radial like shatter from this pretty well.
depending on how you move things around in the points you should get some nice radial shards out of this, if you put a small amount of scatter points on there too, it will start to break up things nicely .
I don't have any time right now to make a hip example, but this should work pretty well for ya
-johnc
make a couple of circles with a limited number of points. say 5 or 7
overlap them slightly and align them to the surface you want to shatter.
pipe their points into the points input of the voroni shatter sop.
and run the shatter.
you should get a radial like shatter from this pretty well.
depending on how you move things around in the points you should get some nice radial shards out of this, if you put a small amount of scatter points on there too, it will start to break up things nicely .
I don't have any time right now to make a hip example, but this should work pretty well for ya
-johnc
Technical Discussion » modify point attribute
- redpaw
- 75 posts
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Graham, thank you for your example file, it helped. but now that I'm trying to put it into use, I'm still not sure if this is going to get me what I want.
I am confused about the “animated” parameters on the geometry chops. I'm using those to feed in 2 parameters, “distance” and “separated”
every time I turn on “animated” on the geometry nodes in the chopnet
and the channel operator, houdini goes into a total updating feedback loop and never stops computing
say I have 2 cubes and their points are overlapping, as they separate I am testing for distance between the points that are near each other, and once they reach a certain distance I want to flag that point as “separated”
but in “animated mode” it seems to never stop computing, and in “static” mode it seems to always use the same value from the first point or something.
I know I need to read the mainual, and watch some tuts, but i am deep in the middle of prod and need to get something working for this Asap.
hope this makes sense.
thanks :-)
-johnc
I am confused about the “animated” parameters on the geometry chops. I'm using those to feed in 2 parameters, “distance” and “separated”
every time I turn on “animated” on the geometry nodes in the chopnet
and the channel operator, houdini goes into a total updating feedback loop and never stops computing
say I have 2 cubes and their points are overlapping, as they separate I am testing for distance between the points that are near each other, and once they reach a certain distance I want to flag that point as “separated”
but in “animated mode” it seems to never stop computing, and in “static” mode it seems to always use the same value from the first point or something.
I know I need to read the mainual, and watch some tuts, but i am deep in the middle of prod and need to get something working for this Asap.
hope this makes sense.
thanks :-)
-johnc
Technical Discussion » Linux graphical issues
- redpaw
- 75 posts
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I'm also seeing this error on expecially long pulldown menus like the one for deleting groups in sops group node, when you have a lot of separate object groups. I'm doing a lot of shattering geo lately, and when
this error happens enough times it starts to turn the pulldown black and the list is offset badly.
this error happens enough times it starts to turn the pulldown black and the list is offset badly.
Technical Discussion » modify point attribute
- redpaw
- 75 posts
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Hi guys, quick question.
Is there a way to set up and use an attribute to flag a piece of geometry for only a certain number of frames?
in code, I'm thinking like add an attribute called separated,
set it to 0,
then modify it with some expression to set separated to 1.
then for every frame after that, if separated is already 1, it should always stay as 1, even if the original modification expression would evaluate it back to 0 again. basically a one way switch attribute.
I know the nature of sops may not handle this, so is this a case for a sop solver within dops?
if it would be possible to do it in sops tho that would be ideal.
if anyone has any ideas that'd be awesome.
thanks in advance
-johnc
Is there a way to set up and use an attribute to flag a piece of geometry for only a certain number of frames?
in code, I'm thinking like add an attribute called separated,
set it to 0,
then modify it with some expression to set separated to 1.
then for every frame after that, if separated is already 1, it should always stay as 1, even if the original modification expression would evaluate it back to 0 again. basically a one way switch attribute.
I know the nature of sops may not handle this, so is this a case for a sop solver within dops?
if it would be possible to do it in sops tho that would be ideal.
if anyone has any ideas that'd be awesome.
thanks in advance
-johnc
Technical Discussion » maya fbx -> houdini bug?
- redpaw
- 75 posts
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Just ran across this myself,
I had hundreds of little pieces of shattered geo coming in via FBX/vertex cache.
I wrote a quick hcript to add a timeShift node into the stack on each object
opcf /obj/file_fbx/geo_Cached_chunks/pieces/
set list = `execute(“opls -d piece*”)`
foreach node($list)
opcf $node
if(`opexist(“timeshift1”)` !=1) then
opadd -n timeshift
endif
opwire -n “vertex_cache” -0 “timeshift1”
chkey -F ‘$F+1’ timeshift1/frame
opset -d on -r on -t on -e on timeshift1
cd ..
end
hope this helps someone else :-)
-johnc
I had hundreds of little pieces of shattered geo coming in via FBX/vertex cache.
I wrote a quick hcript to add a timeShift node into the stack on each object
opcf /obj/file_fbx/geo_Cached_chunks/pieces/
set list = `execute(“opls -d piece*”)`
foreach node($list)
opcf $node
if(`opexist(“timeshift1”)` !=1) then
opadd -n timeshift
endif
opwire -n “vertex_cache” -0 “timeshift1”
chkey -F ‘$F+1’ timeshift1/frame
opset -d on -r on -t on -e on timeshift1
cd ..
end
hope this helps someone else :-)
-johnc
Technical Discussion » dops shatter with sticky textures weirdness
- redpaw
- 75 posts
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Ok kinda figured it out myself after a few peter quint vimeo videos, thanks peter!
Changing the point uv attributes to using a vertex sop uv seems to fix the problem.
One I test it for a little bit, I'll post the modified solver for everybody,
it definitely helps.
-johnc
Changing the point uv attributes to using a vertex sop uv seems to fix the problem.
One I test it for a little bit, I'll post the modified solver for everybody,
it definitely helps.
-johnc
Technical Discussion » dops shatter with sticky textures weirdness
- redpaw
- 75 posts
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I've got another bit of weirdness I'm hoping someone can help me with. Attached is a test file I've put together.
What I'm trying to do is auto fracture at sim time with multiple iterations, and have the texture UVs stay “sticky” to the interior surfaces once they are applied.
Ive accomplished this by inserting a UVtexture node right after the inside group creation point in the voroni fracture sop within the rigid body solver OTL.
I tried a bunch of different ways to do this, but this was the most sucessfull except for one issue. It works with native houdini geo, or stuff you completely UV in houdini, but if you
are trying to use an already uv'd OBJ from a file as the input, it seems to need the “uv” parameters explicitly set, like with a point sop
the only way I have found to get the fracture time UV application to work is if i put a point SOP on the object before the dopImport
However, the point sop, (with add texture on) ends up squishing the UV's at the borders and ruining the good uv layout in some cases.
this is illustrated in the test file.
I'm sure there's a way around this.. anyone?
thanks in advance
-johnc
What I'm trying to do is auto fracture at sim time with multiple iterations, and have the texture UVs stay “sticky” to the interior surfaces once they are applied.
Ive accomplished this by inserting a UVtexture node right after the inside group creation point in the voroni fracture sop within the rigid body solver OTL.
I tried a bunch of different ways to do this, but this was the most sucessfull except for one issue. It works with native houdini geo, or stuff you completely UV in houdini, but if you
are trying to use an already uv'd OBJ from a file as the input, it seems to need the “uv” parameters explicitly set, like with a point sop
the only way I have found to get the fracture time UV application to work is if i put a point SOP on the object before the dopImport
However, the point sop, (with add texture on) ends up squishing the UV's at the borders and ruining the good uv layout in some cases.
this is illustrated in the test file.
I'm sure there's a way around this.. anyone?
thanks in advance
-johnc
Houdini Indie and Apprentice » fracture object scale pieces on impact
- redpaw
- 75 posts
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I would like to use a simple sop solver setup to scale the pieces of a fracture object when they register an impact
right now I'm trying to create an impact group
with
dopnumrecords(“.”, $OBJNAME“, ”Impacts“, ”Impacts“)>=1
to activate the group
and then pipe that into a multi solver with a sop solver that scales down everyting in the group ”impact“
but it doesent seem to work,
the same setup works if I set it up with a single RBD object,
and
dopnumrecords(”.“, ”realNameOfsingleRBDobject“, ”Impacts“, ”Impacts")>=1
but it seems to have to be different with a fracture/glue object
and / or using $OBJNAME instead of the real string name of the object
any help would be greatly appreciated
thanks
-johnc
right now I'm trying to create an impact group
with
dopnumrecords(“.”, $OBJNAME“, ”Impacts“, ”Impacts“)>=1
to activate the group
and then pipe that into a multi solver with a sop solver that scales down everyting in the group ”impact“
but it doesent seem to work,
the same setup works if I set it up with a single RBD object,
and
dopnumrecords(”.“, ”realNameOfsingleRBDobject“, ”Impacts“, ”Impacts")>=1
but it seems to have to be different with a fracture/glue object
and / or using $OBJNAME instead of the real string name of the object
any help would be greatly appreciated
thanks
-johnc
Technical Discussion » spring constraint stiffness issues
- redpaw
- 75 posts
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Hey, I am having an issue with an RBD sim I'm working on,
I have a “tripod” of springs tying my object to the ground and so far, cranking up the spring strength to 1e+16 and damping to 1e07 does not stop the object from being knocked over, I would like it to be sprung to the ground kinda like one of those little kid playground toys with the giant coil spring attached to the animal that the kid rides on.
I'm just not sure at this point that if I keep cranking numbers that it'll ever really do what I want. I want a really stiff damped spring to keep something upright but be able to pelt it with objects (a weeble wobbles but it doesnet fall down) sort of simulation.
Can anyone help me with this? I'm assuming its related to the objects mass or something too? I need some insight into how the spring constraint works I guess..
thanks in advance
-johnc
I have a “tripod” of springs tying my object to the ground and so far, cranking up the spring strength to 1e+16 and damping to 1e07 does not stop the object from being knocked over, I would like it to be sprung to the ground kinda like one of those little kid playground toys with the giant coil spring attached to the animal that the kid rides on.
I'm just not sure at this point that if I keep cranking numbers that it'll ever really do what I want. I want a really stiff damped spring to keep something upright but be able to pelt it with objects (a weeble wobbles but it doesnet fall down) sort of simulation.
Can anyone help me with this? I'm assuming its related to the objects mass or something too? I need some insight into how the spring constraint works I guess..
thanks in advance
-johnc
Technical Discussion » DOPs start frame weirdness...
- redpaw
- 75 posts
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I'm having a problem where I want to have my dops sim start at frame 80, I set the startFrame on the autodop network to 80 and the “Creation frame” on my rbdFractured object is set to frame 1
when I run this sim I sometimes get the rbdObject to initialize correctly, and after a couple times running it, it ends up not initialzing anymore.
if I set everything back to frame 1 then it works properly, but I have to wait thru 80 frames of SLOOW runup of nothing.
is anybody else having this issue? or does my workflow not compute to anyone?
thanks
-johnc
when I run this sim I sometimes get the rbdObject to initialize correctly, and after a couple times running it, it ends up not initialzing anymore.
if I set everything back to frame 1 then it works properly, but I have to wait thru 80 frames of SLOOW runup of nothing.
is anybody else having this issue? or does my workflow not compute to anyone?
thanks
-johnc
Technical Discussion » FBX export failing.
- redpaw
- 75 posts
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Looks like no matter what I do, I always have to run an FBX export with a full frame range (ex 1-200) vs a frame range of say 50-200 or whatever.
if I try to export my dops sim from say 50-200 I end up getting nothing but a locator at the origin exported, if I set it back to 1-200 it will calculate and export everything out properly.
is this a known issue? or am I doing something wrong.
I could only assume, that it might be intentional, if its only “exporting” the geometry at the “first” frame or something? I don't know.
anybody else seen this before?
thanks
-johnc
if I try to export my dops sim from say 50-200 I end up getting nothing but a locator at the origin exported, if I set it back to 1-200 it will calculate and export everything out properly.
is this a known issue? or am I doing something wrong.
I could only assume, that it might be intentional, if its only “exporting” the geometry at the “first” frame or something? I don't know.
anybody else seen this before?
thanks
-johnc
Houdini Lounge » Houdini shattered object animation to Softimage
- redpaw
- 75 posts
- Offline
The main problem we've had so far with the fracturing stuff going back into FBX and then maya is that when it gets there, and you try to render it with motion blur its pretty much useless at the “shattering” frames. because
from what I understand, when fbx is storing the “fractured pieces” it puts all the verts back at 0,0,0 and on that frame they “pop” out.
so the whole object ends up looking totally blurred out when it hits and fractures..
if there's any way around this I'd love to know.
only thing I can think of is offsetting the shutter on the motion blur or something?
anybody else got any ideas on this?
thanks
-johnc
from what I understand, when fbx is storing the “fractured pieces” it puts all the verts back at 0,0,0 and on that frame they “pop” out.
so the whole object ends up looking totally blurred out when it hits and fractures..
if there's any way around this I'd love to know.
only thing I can think of is offsetting the shutter on the motion blur or something?
anybody else got any ideas on this?
thanks
-johnc
Technical Discussion » constant Errors about "Could not Open cursor file
- redpaw
- 75 posts
- Offline
This just started happening and I don't know why?
getting constant “Error: Could not Open cursor file /….grab.png”
Error could not find cursor file hand
and lots of other ones depending on where I move my cursor around the UI.
I'm running on Linux 64 bit and latest 11.0.547 version,
seems tho that a lot of the back versions now exhibit this problem as well.
anybody seen this error before and know how to fix it?
the install and directory with the icons seems fine.
thanks
-johnc
getting constant “Error: Could not Open cursor file /….grab.png”
Error could not find cursor file hand
and lots of other ones depending on where I move my cursor around the UI.
I'm running on Linux 64 bit and latest 11.0.547 version,
seems tho that a lot of the back versions now exhibit this problem as well.
anybody seen this error before and know how to fix it?
the install and directory with the icons seems fine.
thanks
-johnc
Technical Discussion » solaris nebula effect
- redpaw
- 75 posts
- Offline
This is pretty awesome Joe, thanks , one thing, compiling this I'm getting an error in the “Trigonometric” function, it appears that the absolute functions in that are erroring
“error: call of overloaded ‘abs(float)’ is ambiguous”
“error: call of overloaded ‘abs(double)’ is ambiguous”
commenting out that one option makes it all happy.
another question tho, is how do you control the scale of the functions?
I've tried making a new one with two nulls and can't get it to stay in a reasonable world size as in your example..
thanks for any hints..
-johnc
“error: call of overloaded ‘abs(float)’ is ambiguous”
“error: call of overloaded ‘abs(double)’ is ambiguous”
commenting out that one option makes it all happy.
another question tho, is how do you control the scale of the functions?
I've tried making a new one with two nulls and can't get it to stay in a reasonable world size as in your example..
thanks for any hints..
-johnc
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