Thanks! Yes, I've been looking into this a bit more and it seems to be the case.
https://www.sidefx.com/docs/houdini/render/understanding.html [www.sidefx.com] is a good explanation of Mantra's shading process, and using dimport to grab variables from the displacement shader in the surface shader.
I've been looking for similar info on Karma and MaterialX but believe using rest is a good solution for now but was hoping there might be some secret rayimport [www.sidefx.com] or renderstate [www.sidefx.com] type of trick
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Technical Discussion » Karma Get Surface Position Pre-Displacement?
- jkunz07
- 76 posts
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Technical Discussion » Karma Get Surface Position Pre-Displacement?
- jkunz07
- 76 posts
- Online
Here's an example showing what I'm hoping to achieve, I'd like to have the pattern in the surface shader and the displacement noise line up. If I use the mtlxposition node it only grabs the position of the surface being shaded (after it's been displaced). If I read the rest attribute, it gives me the result I'm hoping for but it seems redundant to copy P to rest just to do this. Is it possible to directly read the P attribute or get the pre-displacement surface position in some other way?
Technical Discussion » Karma Get Surface Position Pre-Displacement?
- jkunz07
- 76 posts
- Online
Is it possible to retrieve the pre-displacement surface position in a Karma surface shader?
The only way I've been able to do this at the moment is by copying P to rest or another extra attribute and then reading that attribute in the surface shader.
I'm hoping there's a way to access the P attribute directly or before the displacement shader has run without relying on extra attributes being stored on the geometry.
The only way I've been able to do this at the moment is by copying P to rest or another extra attribute and then reading that attribute in the surface shader.
I'm hoping there's a way to access the P attribute directly or before the displacement shader has run without relying on extra attributes being stored on the geometry.
Edited by jkunz07 - 2022年9月28日 05:48:43
Houdini Learning Materials » Rendering Sand Grains with Redshift for Houdini
- jkunz07
- 76 posts
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This one goes into sand grain modeling, instancing packed primitives, lighting, shading and rendering with Redshift for Houdini.
The first video covers simulation setup and art direction with vellum grains.
Houdini Learning Materials » Vellum Grain Character Disintegration
- jkunz07
- 76 posts
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HOULY Daily Challenge » Day 3 | Elements: Water
- jkunz07
- 76 posts
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HOULY Daily Challenge » Day 2 | Elements: Wind
- jkunz07
- 76 posts
- Online
HOULY Daily Challenge » Day 1 | Elements: Earth
- jkunz07
- 76 posts
- Online
Here's me clay earth !
Did it on stream today if anyone's interested in checking out the process behind this:
Did it on stream today if anyone's interested in checking out the process behind this:
Edited by jkunz07 - 2020年7月2日 01:25:39
Technical Discussion » Where do I assign GPU for Houdini?
- jkunz07
- 76 posts
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You can set it in the preferences now
Edit -> Preferences -> Miscellaneous
OpenCL Device Dropdown
Restart Houdini for it to take effect.
Edit -> Preferences -> Miscellaneous
OpenCL Device Dropdown
Restart Houdini for it to take effect.
Houdini Lounge » Old tutorials before web-site redesign
- jkunz07
- 76 posts
- Online
I've been looking for Mario's implementing spectral colors in Mantra presentation. It seems to have vanished.
Houdini Lounge » Naiad theme for H16 (Circular nodes - one shape to rule them all)
- jkunz07
- 76 posts
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Thanks for clearing that up for me Graham.
Should custom shapes show up in the list returned by doing:
I have test.json (with “name”: “test” specified) file in the config/NodeShapes/ in my home houdini dir.
'test' doesn't show up in the node shapes list, and trying to set the userData ‘nodeshape’ to ‘test’ seems to just give me the standar ‘rect’ shape.
Should custom shapes show up in the list returned by doing:
hou.ui.paneTabOfType(hou.paneTabType.NetworkEditor).nodeShapes()
I have test.json (with “name”: “test” specified) file in the config/NodeShapes/ in my home houdini dir.
'test' doesn't show up in the node shapes list, and trying to set the userData ‘nodeshape’ to ‘test’ seems to just give me the standar ‘rect’ shape.
Houdini Lounge » Naiad theme for H16 (Circular nodes - one shape to rule them all)
- jkunz07
- 76 posts
- Online
Has anyone been able to get custom shapes working?
I've been unable to get the HOUDINI_PATH setup properly. trying something likeIt seems like the shapes in $HFS are still taking precedence over the ones in my home dir.
(This is on Linux)
I've been unable to get the HOUDINI_PATH setup properly. trying something like
HOUDINI_PATH = ${HOME}/houdini16.0/config/NodeShapes;&
(This is on Linux)
Houdini Lounge » Naiad theme for H16 (Circular nodes - one shape to rule them all)
- jkunz07
- 76 posts
- Online
Is the HOUDINI_NODE_WIDTH env no longer supported with H16? It doesn't seem to do anything as far as I've tried.
Houdini Learning Materials » Directional sucktion in pop
- jkunz07
- 76 posts
- Online
Houdini Lounge » H12.5 viewport displays geometry that it's NOT SUPPOSED TO!
- jkunz07
- 76 posts
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This egregious bug seems to be happening more frequently in recent releases. I have noticed it on both osx and linux using builds 15.5.6xx and higher. In some cases the geometry that shouldn't be visible in the viewport even continues to be updated, such as particle simulations that don't have the display flag set any longer.
This is a very frustrating problem to be experiencing.
This is a very frustrating problem to be experiencing.
Edited by jkunz07 - 2017年1月22日 17:50:40
Technical Discussion » Bake Volume On Render To Point Cloud
- jkunz07
- 76 posts
- Online
This is something I've tried in the past but never found a great solution in houdini. It would be great if mantra had an easy solution for baking lighting into a volume or a point cloud.
Technical Discussion » create VDB that matches topology/resolution of existing VDB
- jkunz07
- 76 posts
- Online
Isn't this what vdbactivate is for?
Using it with the value box turned off and in reference mode with activate using vdb's enabled, I was able to get it to produce the same results and slightly faster. If you want the new grid to inherit the transforms/cell size of the reference, you can plug the input of the empty_v_grid node into an output of the reference vdb.
I've tried to attach my findings
off topic:
It would be very useful if we could get some of the newer vdb nodes in houdini like advecting scalar fields or removing divergence from vector fields.
Using it with the value box turned off and in reference mode with activate using vdb's enabled, I was able to get it to produce the same results and slightly faster. If you want the new grid to inherit the transforms/cell size of the reference, you can plug the input of the empty_v_grid node into an output of the reference vdb.
I've tried to attach my findings
off topic:
It would be very useful if we could get some of the newer vdb nodes in houdini like advecting scalar fields or removing divergence from vector fields.
Houdini Lounge » Killing Houdini process from cygwin
Technical Discussion » Transforming Velocity/Direction vector
- jkunz07
- 76 posts
- Online
It seems like maybe I need to extract the scale from the matrix and multiply the velocity by that as well?
Technical Discussion » Transforming Velocity/Direction vector
- jkunz07
- 76 posts
- Online
If I want to transform a velocity vector by a matrix4, do I just multiply it by the transpose(inverse(matrix4))?
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