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Technical Discussion » Node dependencies in Python
- ralphymeijer
- 15 posts
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Technical Discussion » New 18.499 Guide Deform Issues
- ralphymeijer
- 15 posts
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Hey guys,
I'm running into an issue with the new guide deform in 18.499 and I'm hoping someone can help me in the right direction. Maybe I'm using it wrong so please correct me if I do so.
In our pipeline we get a groom from Maya exported as alembic curves. These are all the render hairs. In Houdini I'm filtering a percentage of it that I can use for simulation or other things I need to do with them. When I'm done I can use these guide curves to deform the full groom. Obviously the Guide deform should be able to do this. The new guide deform in 18.499 is allready a lot better but I'm still getting artifacts.
So this is the full patch of hair as an example.
These are the guides I'm extracting:
The guides that are deformed:
So when I use the guide deform with barycentric weights it comes pretty close but there are artifact where the tips are not deformed correctly.
Even if I generate new hairs from the guides with the hairgen sop and tick on computes weights. And use the existing weights mode it still has the issue with the tips.
With the existing weights it is definitely following the guides better. I could even try to compute the weights myself on the original render groom. However I would still run into the tips issue.
In the past we just made sure we had enough guides and generate new render hairs from that. We sort of got away with that but it's not as accurate as deforming the original groom.
Hopefully someone can shed a light on it.
Thanks in advance!
Ralph
I'm running into an issue with the new guide deform in 18.499 and I'm hoping someone can help me in the right direction. Maybe I'm using it wrong so please correct me if I do so.
In our pipeline we get a groom from Maya exported as alembic curves. These are all the render hairs. In Houdini I'm filtering a percentage of it that I can use for simulation or other things I need to do with them. When I'm done I can use these guide curves to deform the full groom. Obviously the Guide deform should be able to do this. The new guide deform in 18.499 is allready a lot better but I'm still getting artifacts.
So this is the full patch of hair as an example.
These are the guides I'm extracting:
The guides that are deformed:
So when I use the guide deform with barycentric weights it comes pretty close but there are artifact where the tips are not deformed correctly.
Even if I generate new hairs from the guides with the hairgen sop and tick on computes weights. And use the existing weights mode it still has the issue with the tips.
With the existing weights it is definitely following the guides better. I could even try to compute the weights myself on the original render groom. However I would still run into the tips issue.
In the past we just made sure we had enough guides and generate new render hairs from that. We sort of got away with that but it's not as accurate as deforming the original groom.
Hopefully someone can shed a light on it.
Thanks in advance!
Ralph
Technical Discussion » Float attribute on curves & Alembic to maya
- ralphymeijer
- 15 posts
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Hey what are you using for rendering in Maya. We do the same thing but use vray proxies to do the hair rendering. Works really well with extra attributes. I'm sure there is a similar workflow possible with any other renderer. You are correct that in maya you can't read extra attributes from curves.
Good luck!
Ralph
Good luck!
Ralph
Technical Discussion » Where is the Substance SOP?
- ralphymeijer
- 15 posts
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Are you On linux? I believe it's windows only unfortunately. Hopefully there will be a Linux version soon.
Technical Discussion » PyAlembic in Houdini
- ralphymeijer
- 15 posts
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Hey all,
I was wondering if it is possible to use PyAlembic in houdini. I know there is the alembic extension but it is quite limited to wat it can do. For pipeline purposes I want to get some metadata from the top level node. This is as far as I know not really possible with the extension. However with PyAlembic I can access the top level with the getTop() function.
Is it really necessary to compile PyAlembic for houdini myself or is there an other way to get it to work from within houdini.
Thanks in advance!
Ralph
I was wondering if it is possible to use PyAlembic in houdini. I know there is the alembic extension but it is quite limited to wat it can do. For pipeline purposes I want to get some metadata from the top level node. This is as far as I know not really possible with the extension. However with PyAlembic I can access the top level with the getTop() function.
Is it really necessary to compile PyAlembic for houdini myself or is there an other way to get it to work from within houdini.
Thanks in advance!
Ralph
PDG/TOPs » How to correctly use ROP Alembic
- ralphymeijer
- 15 posts
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Never mind I found the sort node. Thank you very much for your help! I think I figured it out.
PDG/TOPs » How to correctly use ROP Alembic
- ralphymeijer
- 15 posts
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Thanks for your reply!
I expected that since it sort of worked when I tried that before. However is there a way to sort the workitems based on for example an attribute. Now the workitems are sorted the following: box.0001.bgeo, sphere.0001.bgeo, torus.0001.bgeo, box.0002.bgeo, sphere.0002.bgeo etc. It would be handy if I could sort them box.0001.bgeo, box.0002.bgeo, sphere.0001.bgeo, sphere.0002.bgeo etc. That way I can still split them in the wanted files based on the frame range.
I expected that since it sort of worked when I tried that before. However is there a way to sort the workitems based on for example an attribute. Now the workitems are sorted the following: box.0001.bgeo, sphere.0001.bgeo, torus.0001.bgeo, box.0002.bgeo, sphere.0002.bgeo etc. It would be handy if I could sort them box.0001.bgeo, box.0002.bgeo, sphere.0001.bgeo, sphere.0002.bgeo etc. That way I can still split them in the wanted files based on the frame range.
PDG/TOPs » How to correctly use ROP Alembic
- ralphymeijer
- 15 posts
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I'm testing some setups to automate some vellum sim jobs where I load different type of collision objects coming from shots,process them and then write out the result per shot to alembic. The first bit is working fine as expected where I load in the collision objects with a file pattern, in this example I have 3 objects. Then I use the Rop Geometry to process them for 150 frames, creating a total of 450 work items. I then partition them based on the original object so I got 3 work items again. This is what I feed in to the Rop Alembic. This is where I can't get it to work and it's probably my lack of knowledge of PDG. What is the correct way of using the Rop Alembic in this case. I tried looking at the examples but that only handles single frame alembics.
Hope someone can help. Thanks in advance!
Hope someone can help. Thanks in advance!
Edited by ralphymeijer - 2019年9月9日 17:08:11
Technical Discussion » python filepath save in background not rendering
- ralphymeijer
- 15 posts
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Hi guys,
We are updating our shotgun alembic rops to have the save in background functionality which was not previously available. Nothing that special. We have a python expression in the filepath to set the correct output based on the shotgun context. This works fine with the regular save to disk, however it doesn't work with save to disk in background. I suggest it has something to updating the line of python. When sending to background are there any other things happening? Internally saving it to a different location perhaps? This can affect the eventual output path with the python expression.
The line of code is also not that special
We are updating our shotgun alembic rops to have the save in background functionality which was not previously available. Nothing that special. We have a python expression in the filepath to set the correct output based on the shotgun context. This works fine with the regular save to disk, however it doesn't work with save to disk in background. I suggest it has something to updating the line of python. When sending to background are there any other things happening? Internally saving it to a different location perhaps? This can affect the eventual output path with the python expression.
The line of code is also not that special
import hou node = hou.node("..") parm = node.parm("filename") parm_token = parm.menuItems()[parm.eval()] if parm_token == "sgtk": parm_label = parm.menuLabels()[parm.eval()] if not parm_label.startswith("ERROR"): return hou.expandString(parm_label) return ""
Technical Discussion » Hide perpective grid with python
- ralphymeijer
- 15 posts
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Technical Discussion » Hide perpective grid with python
- ralphymeijer
- 15 posts
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Hey guys,
Does anyone of you know how to hide the grid in the perspective view with python. There is a function setDisplayOrthoGrid() but this is only for the ortographic views. Calling this function in the perspective view does nothing. Only by switching back and forth to an orhographic view this will be updated in the perspective view. There is a ui button so you would think it would be possible with python.
Thanks in advance!
Ralph
Does anyone of you know how to hide the grid in the perspective view with python. There is a function setDisplayOrthoGrid() but this is only for the ortographic views. Calling this function in the perspective view does nothing. Only by switching back and forth to an orhographic view this will be updated in the perspective view. There is a ui button so you would think it would be possible with python.
Thanks in advance!
Ralph
PDG/TOPs » $JOB/$HIP variable not correctly evaluating with rop?
- ralphymeijer
- 15 posts
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PDG/TOPs » $JOB/$HIP variable not correctly evaluating with rop?
- ralphymeijer
- 15 posts
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This is the first time I'm playing with PDG so this might be a user error but I'm having issues with the ropgeometry. It seems to correctly generate all the wedges if I set an absolute path, but when I use the $JOB or $HIP variable it seems the output variable doesn't evaluate properly. The expected outputpath is correct but the final path is not. It will write to my default home folder. Is there something that I'm doing wrong?
Thanks!
Ralph
Thanks!
Ralph
Edited by ralphymeijer - 2019年5月8日 05:04:33
Technical Discussion » Write console to file
- ralphymeijer
- 15 posts
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Hey All,
We are running Houdini with Shotgun on Linux. For the development of Shotgun apps we need feedback from the python scripts we are writing. On windows we have the console to check all the activity. On Linux we would be launching Houdini from the terminal. However this is not possible because that way the Shotgun context is not loaded and Shotgun won't work. So I need to launch Houdini from the Shotgun launcher. A work around would be to write the stdout to a file which I then check that file. However I don't get that to work. It seems things get overridden by ShellIO.
Does anyone have a clue how to get this to work or any other way to get a console?
Thanks in advance!
Ralph
We are running Houdini with Shotgun on Linux. For the development of Shotgun apps we need feedback from the python scripts we are writing. On windows we have the console to check all the activity. On Linux we would be launching Houdini from the terminal. However this is not possible because that way the Shotgun context is not loaded and Shotgun won't work. So I need to launch Houdini from the Shotgun launcher. A work around would be to write the stdout to a file which I then check that file. However I don't get that to work. It seems things get overridden by ShellIO.
Does anyone have a clue how to get this to work or any other way to get a console?
Thanks in advance!
Ralph
Technical Discussion » Drag force Flip fluid
- ralphymeijer
- 15 posts
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Hi all,
I'm new to Houdini and learning the flip solver. I want to add some drag to my sim. However I'm not sure where to add the drag force. Can I just add it before or after the gravity or should I use an input in the solver?
Thanks in advance!
Ralph
I'm new to Houdini and learning the flip solver. I want to add some drag to my sim. However I'm not sure where to add the drag force. Can I just add it before or after the gravity or should I use an input in the solver?
Thanks in advance!
Ralph
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