Hey, I've been trying to use the VDB Reshape SDF node, but it's not working, and kicking up this error for me:
“VDB primitive density was skipped because it is not a level-set grid.”
Can anyone tell me what that means, and how to solve it? Thanks!
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Technical Discussion » VDB Reshape SDF Error
- Tooloohoohoo
- 9 posts
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Technical Discussion » Simple render queue for one machine?
- Tooloohoohoo
- 9 posts
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Technical Discussion » Simple render queue for one machine?
- Tooloohoohoo
- 9 posts
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Hey everybody. Is there a way to render several files in sequence without using HQueue? I have a single workstation where I'd like to just locally queue up several files to render overnight, or over a weekend.
Technical Discussion » Finding Normal Distance to Zero-Thickness
- Tooloohoohoo
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Thanks for the alternate method. I've already set up the original one though, which works for me, so I'll stick with that. But it's good to know that the other way is also a possibility.
Technical Discussion » Finding Normal Distance to Zero-Thickness
- Tooloohoohoo
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That did the trick, thanks!
For anyone stumbling upon this in the future trying to solve the same problem, here are a couple things to note that I learned along the way:
The intersect node checks against a default cube that is not shown in the scene at all, unless you feed it the geo you want specifically. Maybe this was a noob mistake on my part (I've never used that node before), but it wasn't well documented. My assumption was that it would find the first collision with anything, and I was struggling for a while that I was getting a result that did not make sense. The solution was to feed it the geo to collide against.
When projecting inward to check collision with the opposite inner face of the same model, it will instead collide with itself, giving a ray of zero length. The way to get around this is to stick a Peak module on the geo on the version you're checking for collisions, with a tiny push outward (I used 0.00001), just enough to let the ray pass inward.
A good way to keep it from jumping through from a missed ray check between solver frames is to compare the previous frame's ray value versus the current one. The rays should always be shrinking, so if the current one is larger than the last, that means it punched through, and you should replace that with 0 to stop it moving.
A-OC, thanks again for pointing me in the right direction!
For anyone stumbling upon this in the future trying to solve the same problem, here are a couple things to note that I learned along the way:
The intersect node checks against a default cube that is not shown in the scene at all, unless you feed it the geo you want specifically. Maybe this was a noob mistake on my part (I've never used that node before), but it wasn't well documented. My assumption was that it would find the first collision with anything, and I was struggling for a while that I was getting a result that did not make sense. The solution was to feed it the geo to collide against.
When projecting inward to check collision with the opposite inner face of the same model, it will instead collide with itself, giving a ray of zero length. The way to get around this is to stick a Peak module on the geo on the version you're checking for collisions, with a tiny push outward (I used 0.00001), just enough to let the ray pass inward.
A good way to keep it from jumping through from a missed ray check between solver frames is to compare the previous frame's ray value versus the current one. The rays should always be shrinking, so if the current one is larger than the last, that means it punched through, and you should replace that with 0 to stop it moving.
A-OC, thanks again for pointing me in the right direction!
Technical Discussion » Finding Normal Distance to Zero-Thickness
- Tooloohoohoo
- 9 posts
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Thanks for the reply!
That is the look I'm trying to achieve. However, I probably should have explained my needs a bit more. Specifically what I need is a value that is that distance to zero thickness, which I can transfer over to vertex colors or UV values, because this is for a game mesh. The actual squeeze along the normal direction will take place in the game engine on the polygonal mesh, not in Houdini, and I need a value to clamp the push distance for, on a per-vertex basis. Also that clamping will drive opacity, so the vertices that hit zero thickness can be made invisible.
Your solution of converting to a VDB and eroding is very cool and works fine for Houdini, but won't work for my needs on this game.
That is the look I'm trying to achieve. However, I probably should have explained my needs a bit more. Specifically what I need is a value that is that distance to zero thickness, which I can transfer over to vertex colors or UV values, because this is for a game mesh. The actual squeeze along the normal direction will take place in the game engine on the polygonal mesh, not in Houdini, and I need a value to clamp the push distance for, on a per-vertex basis. Also that clamping will drive opacity, so the vertices that hit zero thickness can be made invisible.
Your solution of converting to a VDB and eroding is very cool and works fine for Houdini, but won't work for my needs on this game.
Technical Discussion » Finding Normal Distance to Zero-Thickness
- Tooloohoohoo
- 9 posts
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Hey everyone!
Can anyone point me in the right direction for how to determine on air-tight geometry the distance it would take to push each point inward along the normal (like the Peak nodes does, if you give it negative numbers) until it hits the other side, getting pushed in at the same rate?
Right now if you use the Peak node with negative numbers of increasing magnitude on a mesh that has parts of variable thickness, the thinner parts will eventually start turning inside-out. What I want is for them to stop right before that happens and stay at a thickness of zero, so they squeeze down to invisibility, while the thicker parts of the mesh continue to push inward.
Thanks!
Can anyone point me in the right direction for how to determine on air-tight geometry the distance it would take to push each point inward along the normal (like the Peak nodes does, if you give it negative numbers) until it hits the other side, getting pushed in at the same rate?
Right now if you use the Peak node with negative numbers of increasing magnitude on a mesh that has parts of variable thickness, the thinner parts will eventually start turning inside-out. What I want is for them to stop right before that happens and stay at a thickness of zero, so they squeeze down to invisibility, while the thicker parts of the mesh continue to push inward.
Thanks!
Technical Discussion » Micropolygon Renderer Artifacts
- Tooloohoohoo
- 9 posts
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Technical Discussion » Micropolygon Renderer Artifacts
- Tooloohoohoo
- 9 posts
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Hi. I've been having a problem rendering Pyro using the Micropolygon renderer. Most frames turn out fine, but once in while, maybe one frame out of 20 or 30, there is a rendering artifact of bright vertical streaks. See the attached image, where I show one frame looking fine, and the next with the artifacts.
This problem does not happen when I use Ray Tracing, so I've been doing that so far on final renders. However all documentation says that Micropolygon is the way the go with Pyro, and it does seem to render faster, considering I have to crank the sampling very high on Ray Tracing to get equally smooth vapor.
I'm new to Houdini, but have done several Pyro assets by now, and seen the problem with all of them.
Can anyone help me?
Thanks!
This problem does not happen when I use Ray Tracing, so I've been doing that so far on final renders. However all documentation says that Micropolygon is the way the go with Pyro, and it does seem to render faster, considering I have to crank the sampling very high on Ray Tracing to get equally smooth vapor.
I'm new to Houdini, but have done several Pyro assets by now, and seen the problem with all of them.
Can anyone help me?
Thanks!
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