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Houdini Learning Materials » Basic CHOPs question: converting data (?)
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Here is an image and a flipbook animation representing the curve in the image. The flipbook is indicative of the type of “disturbance” that I am giving the “record-platter” with my back-and-forth motion on the platter. However currently the results are not as accurate as I had hoped. It is quite difficult for me to test this against a real audio file that is being “scratched” since I do not yet have all of the necessary hardware that would interpret this. But I am headed in the right direction thanks to your CHOPs suggestions edward.
Houdini Learning Materials » Basic CHOPs question: converting data (?)
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Using a combination of the Area CHOP to generate the initial revolutions (which are applied to a geometry to get the geom to rotate) and combining it with the Spectrum CHOP as you suggested, to get the peaks of high frequency (where high frequency refers to the manual rotation of the turntable platter that I am applying in a back-and-forth motion as would be the case when scratching a record)… Trimming the result of the Spectrum CHOP before applying a combination using Math CHOP … gives me a result that looks right though I can't test the audio that well at the moment (I am doing a system backup and don't want to overload the backup). I will report with a full JPG image of the Motion View to show you my graphs in CHOPs and perhaps add a flipbook animation if that is possible. (Okay, my backup just konked out. Let me see what I can show you in a moment.)
P.S. I have seen that book and as a matter of fact quite some time ago read a good part of it though visually it is difficult to discern the information that is being presented. It is an excellent resource but I just have to get accustomed to the presentation so that I can get what I need out of the information in it.
P.S. I have seen that book and as a matter of fact quite some time ago read a good part of it though visually it is difficult to discern the information that is being presented. It is an excellent resource but I just have to get accustomed to the presentation so that I can get what I need out of the information in it.
Houdini Learning Materials » Basic CHOPs question: converting data (?)
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Okay, thanks. The area chop works nicely, to some degree. The problem that I need to address, which I tried to explain in my second question, was the pulse for the area chop.
My waveform modulates from the standard triangle (/\/\/\/\/\/\/\/\/\) to something that introduces variation in the regularity of the triangle wave.
so /\/\/\/—\/'''\/\/\/^^^\/\ is the same as /\/\/\/\/\/\/\/\/\/\/\ but with some variance in betwixt the peaks and valleys.
How can I take the first waveform which just is a recording of the triangle wave representing platter revolutions and combine it with the one where there is platter revolution on the turntable, “combined” with platter modulations (record-movement-by-hand, a record-scratch if you will) and retrieve the pulse information that would alter the area CHOP?
Does my question make sense now?
My waveform modulates from the standard triangle (/\/\/\/\/\/\/\/\/\) to something that introduces variation in the regularity of the triangle wave.
so /\/\/\/—\/'''\/\/\/^^^\/\ is the same as /\/\/\/\/\/\/\/\/\/\/\ but with some variance in betwixt the peaks and valleys.
How can I take the first waveform which just is a recording of the triangle wave representing platter revolutions and combine it with the one where there is platter revolution on the turntable, “combined” with platter modulations (record-movement-by-hand, a record-scratch if you will) and retrieve the pulse information that would alter the area CHOP?
Does my question make sense now?
Houdini Learning Materials » Basic CHOPs question: converting data (?)
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There's more to the puzzle about this topic. When I move the platter back-and-forth as in a “record scratch” the waveform that exists modulates somewhat. Instead of this type of wave
/\/\/\/\/\/\/\/\/\/\
I get /-_/\^/
or something like that.
What I really need is to have a flat-line that steadily ramps up with the record-movement being highlighted as obvious modulations within the waveform. How can I use the combination of available CHOPs to manipulate the MIDI-In data to expose the data that I am looking for?
Thanks once again in advance.
/\/\/\/\/\/\/\/\/\/\
I get /-_/\^/
or something like that.
What I really need is to have a flat-line that steadily ramps up with the record-movement being highlighted as obvious modulations within the waveform. How can I use the combination of available CHOPs to manipulate the MIDI-In data to expose the data that I am looking for?
Thanks once again in advance.
Houdini Learning Materials » Basic CHOPs question: converting data (?)
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How can I convert from one graph to the next?
In the first graph I have MIDI In data which produces somewhat of a triangle wave. In the second I have a ramp which extends from 0-1 across the entire animation range, 1 being at the end of the animation, 0 at the beginning. How can I convert between the two graphs, changing the triangle wave into the ramp? In other words this data is coming from a turntable and I need it to rotate and accumulate data, not start again at 0 once the first and subsequent revolutions are completed.
Any help is greatly appreciated.
In the first graph I have MIDI In data which produces somewhat of a triangle wave. In the second I have a ramp which extends from 0-1 across the entire animation range, 1 being at the end of the animation, 0 at the beginning. How can I convert between the two graphs, changing the triangle wave into the ramp? In other words this data is coming from a turntable and I need it to rotate and accumulate data, not start again at 0 once the first and subsequent revolutions are completed.
Any help is greatly appreciated.
Technical Discussion » UT_NetPacket error (rendering to ip)
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I have one file launched which is quite a heavy file. It throws the following error when trying to render to a Mantra via ip or to View Mantra:
UT_NetPacket::write: UT_NetPacket::read: Invalid argument
No such file or directory
mantra: Error writing data to image device
UT_NetPacket::write: Invalid argument
UT_NetPacket::read: No such file or directory
mantra: Error writing data to image device
—–
when I open a second instance of houdini with no Mantras but just a platonic solid (for example) and do a View Mantra it renders the entire frame. For the first file it renders one chunk of the image (such as a 64x64 pixel area) and then cancels out without errors except the one i listed above.
Any suggestions? I have seen some posts on odforce from 2003 about this issue but I am running Houdini FX 13.0.260 currently . I am on Windows 7 64-bit SP 1. I ran into this problem with this file once before and restarting the machine fixed the error and allowed me to render the entire image and 6000 images to disk. But now I can't get anything to render from this file.
UT_NetPacket::write: UT_NetPacket::read: Invalid argument
No such file or directory
mantra: Error writing data to image device
UT_NetPacket::write: Invalid argument
UT_NetPacket::read: No such file or directory
mantra: Error writing data to image device
—–
when I open a second instance of houdini with no Mantras but just a platonic solid (for example) and do a View Mantra it renders the entire frame. For the first file it renders one chunk of the image (such as a 64x64 pixel area) and then cancels out without errors except the one i listed above.
Any suggestions? I have seen some posts on odforce from 2003 about this issue but I am running Houdini FX 13.0.260 currently . I am on Windows 7 64-bit SP 1. I ran into this problem with this file once before and restarting the machine fixed the error and allowed me to render the entire image and 6000 images to disk. But now I can't get anything to render from this file.
Technical Discussion » Foreach or not Foreach?
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I solved the issue without using Foreach. I am posting a file. I have locked a null node inside the file which needs to remain locked since I am not providing the associated vector art.
Technical Discussion » Foreach or not Foreach?
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This should probably be asked in the Apprentice section since it is more or less basic and is based on watching Peter Quint's tuts on ForEach on vimeo.
I have a set of 6 or 7 closed polygons that I created in a vector drawing program and imported into Houdini. I now want to copy a random item of the 6 or 7 groupings to each point on a resampled curve which has maybe 50 points on it. It could have 100 or more if I resampled more. The idea is to create a curve with a random polygon array of copied geometry. I'm thinking Foreach and copy-stamping but don't know quite how to go about it since I'm having trouble with the way I'm implementing Foreach. I was watching video #3 for this particular method in the vimeo videos.
Any help would be greatly appreciated. Thanks in advance.
I have a set of 6 or 7 closed polygons that I created in a vector drawing program and imported into Houdini. I now want to copy a random item of the 6 or 7 groupings to each point on a resampled curve which has maybe 50 points on it. It could have 100 or more if I resampled more. The idea is to create a curve with a random polygon array of copied geometry. I'm thinking Foreach and copy-stamping but don't know quite how to go about it since I'm having trouble with the way I'm implementing Foreach. I was watching video #3 for this particular method in the vimeo videos.
Any help would be greatly appreciated. Thanks in advance.
Technical Discussion » MIDI OUT from baked channels (into .mid file)?
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Thanks for your reply. I will look into your file shortly. But the explanation you gave seems to make much sense. I will try it on my own as well as looking at your file.
There is a larger problem and that is what to do with the MIDI data once I have it since I have tried something with CHOPS in a different way for the same project and can't seem to interpret the curve properly, meaning I don't know what to do with the CHOPS curve that I have (animation curve, that is).
There is a larger problem and that is what to do with the MIDI data once I have it since I have tried something with CHOPS in a different way for the same project and can't seem to interpret the curve properly, meaning I don't know what to do with the CHOPS curve that I have (animation curve, that is).
Technical Discussion » ATAN2 in Sops > ?? in Chops
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Thanks tamte. I did figure it out in the meantime by using a Fetch chop which I tried to do initially but incorrectly. This time I used Fetch by posting my SOP rz values to OP level inside of a null object different than the one where I got the file sop to read a geometry render. (At first when I tried to use Fetch on SOP channels it didn't work, but I was probably doing something else wrong). Now the tricky part is trying to interpret the rz data that I have into something meaningful which will manipulate other data that I have. I can't really post a file since it's for an exclusive project concept that I'm working on, but if I have further general questions I will post them to the appropriate forum section. Thanks for reading and responding. :-)
Technical Discussion » ATAN2 in Sops > ?? in Chops
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Hi. I have an atan2 expression which is taking x,y point positions from a file sop of rendered geometry and I'm trying to bring the rz value into Chops. Oddly enough though, when I use the Geometry Chop I get 2 values: rx and ry with a 0 value for rz. In Sop level that rz is populated with rotational values but the rx and ry are zeroed out.
It is evident by this question that I don't quite understand atan2 expressions and how they interplay between sop level and bringing that data into chops.
Can someone explain how to get my rz values to show up as a single channel in chops? Thanks in advance.
It is evident by this question that I don't quite understand atan2 expressions and how they interplay between sop level and bringing that data into chops.
Can someone explain how to get my rz values to show up as a single channel in chops? Thanks in advance.
Technical Discussion » MIDI OUT from baked channels (into .mid file)?
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Hi. Is it possible to bake channels from SOP level into CHOPS and then export that data into a midi file? I think I've tried exporting a .mid before without success. Is there a particularity about doing this correctly?
Thanks in advance.
Thanks in advance.
Houdini Lounge » workaround for Triangulate/Quadrangulate?
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Thank you grayO . . . your explanation seems to make perfect sense. Unfortunately I am not a Houdini user (probably in the minority here) who is well versed in scripting, especially not python. I once knew a little Hscript years ago but only scratching the surface to open corrupt files and fix the display flag of a bad sop and resave.
I would like to know where I can begin to investigate how to write python scripts for Houdini. I know a little ECMA (Actionscript) but only a little, though I am learning more daily. Can you point me in the right direction? Books, links, etc? I once bought a children's python book to see how turtle works as I recall this drawing program from elementary school.
I would like to know where I can begin to investigate how to write python scripts for Houdini. I know a little ECMA (Actionscript) but only a little, though I am learning more daily. Can you point me in the right direction? Books, links, etc? I once bought a children's python book to see how turtle works as I recall this drawing program from elementary school.
Technical Discussion » sort by relative point proximity
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Here is a partially working solution using colors combined with normals to define partitions and connectivity
Technical Discussion » sort by relative point proximity
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What I really need to be able to do is to group each pair of triangles that share the same normal direction down to a very small variance in normal direction. That way I can use pairs of triangles if the geometry is regular enough.
Technical Discussion » sort by relative point proximity
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as you can see in this second file the quadrangulate does not really work. In my case I do not know how to group pairs of faces and use a primitive sop to reduce the prim face scale. I would get prims that are scaled down but separated triangles and this is no good to use the connectivity sop. Let's see if anyone can add to this post because I think I have a good concept going but not the right knowledge about Houdini.
Technical Discussion » sort by relative point proximity
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That works perfectly! Here are the steps for Quadrangulating a divided Torus:
1. Make Quad Poly (in my case a Torus)
2. Fuse Uniqe the points to individualize each face
3. Primitive Sop to scale down each face (separate them in prep for connectivity and partition sops)
4. Divide Sop to triangulate the faces
5. Fuse (disabled)
6. Connectivity Sop to add CLASS attribute to each connected face (pairs of triangles)
7. Partition Sop to create groups for pairs of triangles
8. Foreach SOP to a) sort the faces by vertex order and b) delete the inner edge that defines the triangles
9. Convert SOP to force poly creation in case the last sop evaluates to bad geometry
10. Primitive SOP to reverse invert/reverse the scaling from step 3
11. Fuse to make faces connected at vertices.
The Only problem is in the event that there are some face pairs that do not exist, in other words some faces on more complex geometry are only a single triangle. How would I create a condition that forces those triangles to be skipped in the foreach sop where the edge is deleted?
1. Make Quad Poly (in my case a Torus)
2. Fuse Uniqe the points to individualize each face
3. Primitive Sop to scale down each face (separate them in prep for connectivity and partition sops)
4. Divide Sop to triangulate the faces
5. Fuse (disabled)
6. Connectivity Sop to add CLASS attribute to each connected face (pairs of triangles)
7. Partition Sop to create groups for pairs of triangles
8. Foreach SOP to a) sort the faces by vertex order and b) delete the inner edge that defines the triangles
9. Convert SOP to force poly creation in case the last sop evaluates to bad geometry
10. Primitive SOP to reverse invert/reverse the scaling from step 3
11. Fuse to make faces connected at vertices.
The Only problem is in the event that there are some face pairs that do not exist, in other words some faces on more complex geometry are only a single triangle. How would I create a condition that forces those triangles to be skipped in the foreach sop where the edge is deleted?
Technical Discussion » sort by relative point proximity
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I am trying to sort a set of points that define a polygonal circle. I have randomly sorted the point numbers based on the random tab in the Sort SOP. Now what I am trying to do is to sort them by radial order, perhaps using an expression in a second Sort SOP. But I don't know how to go about this. I have tried creating an id attribute and sorting by that but I see no change. I have also tried to sort by the expression cos($ID) and cos($PT) but no change.
How do I sort radially in order? Thanks in advance. (This also has to do with an idea I have for creating a quadrangulate procedure).
How do I sort radially in order? Thanks in advance. (This also has to do with an idea I have for creating a quadrangulate procedure).
Houdini Lounge » workaround for Triangulate/Quadrangulate?
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I know it is possible to use Triangulate2D or Tetrahedralize on 2D surfaces (tetra must be put into 3D space first with adjustments to the points of the surface) in order to tessalate geometry (polys).
What I am interested in is making Quads from tessalated triangles on a surface.
Let us suppose I have the letter L drawn in a cursive way and it is a Poly that does not require the Hole SOP. Let us also suppose I resampled the edges uniformly placing evenly spaced points around the edges and tesselated the geometry.
My thinking is that I could somehow in a process take 2 groups: The first group groups 0 to n number of polys 2 at a time and the second does the same starting with the alternate beginning set of 2 polys that was not captured in the first group. I could then dissolve the inner edge of the triangle pair using a Divide SOP and removing shared edges. But what if my poly count is random? And what if the point count is random or ordered?
Would it be possible through CHOPS or some other attribute transfer method to reorder the polys according to their connection to one another? Starting with one end of the entire piece of geometry and working the way around? I have tried the connectivity and partition sops without success.
Any suggestions?
What I am interested in is making Quads from tessalated triangles on a surface.
Let us suppose I have the letter L drawn in a cursive way and it is a Poly that does not require the Hole SOP. Let us also suppose I resampled the edges uniformly placing evenly spaced points around the edges and tesselated the geometry.
My thinking is that I could somehow in a process take 2 groups: The first group groups 0 to n number of polys 2 at a time and the second does the same starting with the alternate beginning set of 2 polys that was not captured in the first group. I could then dissolve the inner edge of the triangle pair using a Divide SOP and removing shared edges. But what if my poly count is random? And what if the point count is random or ordered?
Would it be possible through CHOPS or some other attribute transfer method to reorder the polys according to their connection to one another? Starting with one end of the entire piece of geometry and working the way around? I have tried the connectivity and partition sops without success.
Any suggestions?
Technical Discussion » attribute transfer (UV's) (continuation of "Power Carve
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Jeff. I couldn't thank you more. I've been using Carve for a very very long time and I never explored the breakpoints option as I never really learned how it is used (when someone showed me the carve sop years ago). This is a perfect and elegant solution and saves me lots of resources by forgoing the need to invest in a Maya license just for the sake of an important tool in my workflow: The tool already exists in Houdini! GREAT!!!
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