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Technical Discussion » Vellum collision - what am I doing wrong?
- AndyW
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As you can see in the example file, I'm trying to settle the cloth on the floor to create some gathering and bunching, I'm new to Vellum so I'm sure I'm wiring this wrong because it's not working. Any pointers are greatly appreciated
Technical Discussion » @id attribute with copy stamp (point change number during simulation)
- AndyW
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I prefer to set copy stamp attributes on the points/particles themselves and reference that in the copy SOP, it's more controllable and predictable. Also, a lot of the erratic motion you're getting is coming from the transforms you have on your copy geo, but I'm not sure what you're after. The enclosed file is how I would go about it, I hope it's helpful
Technical Discussion » timeshift material texture on Each copyed geometry
- AndyW
- 336 posts
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On second thought, Renderstate won't work because it's called at render time, AFAIK textures are called in and filtered prior to rendering. I think this is a task for Material Stylesheets
Technical Discussion » timeshift material texture on Each copyed geometry
- AndyW
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I haven't had the time to test it, but my bet is you could build a string attribute on your copied geo to set the filepath and frame number using sprintf(), and query that with a Renderstate piped into your file texture in your material. I haven't done this with file textures, but it works great with geometry so I don't see why not.
https://www.sidefx.com/docs/houdini/vex/functions/renderstate.html [www.sidefx.com]
https://www.sidefx.com/docs/houdini/vex/functions/sprintf.html [www.sidefx.com]
https://www.sidefx.com/docs/houdini/vex/functions/renderstate.html [www.sidefx.com]
https://www.sidefx.com/docs/houdini/vex/functions/sprintf.html [www.sidefx.com]
Technical Discussion » Rendering outside of $HIP
- AndyW
- 336 posts
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Why is it that necessary? Why not just make a path variable called $RENDERS or something, then it won't matter where your save your HIP files?
Technical Discussion » Desperately need some guidance with creating a field of dynamics objects and constraints
- AndyW
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Technical Discussion » Desperately need some guidance with creating a field of dynamics objects and constraints
- AndyW
- 336 posts
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Is there a reason they need to be rigid objects? Seems like this is something better accomplished with a noise field on the endpoint of the curves, with the flowers copied to those same points. It might help if you post your current hip file
Technical Discussion » Grab the Geometry node name in SOPS
- AndyW
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Technical Discussion » Grab the Geometry node name in SOPS
- AndyW
- 336 posts
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How would I go about getting the name of the current geometry container in SOPS? Thanks!
Technical Discussion » Set normals to point at camera, VEX
- AndyW
- 336 posts
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I guess I should've been more specific in that I didn't really need to deal with normals other than that being an easy way to rotate instanced or copied geometry. without an up vector the geometry tends to rotate weirdly around it's local z axis, setting an up vector and using @orient fixes that. I've never used cracktransform, I'll have to dig into that
Technical Discussion » Set normals to point at camera, VEX
- AndyW
- 336 posts
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Ok here's what seems to work best, set @orient instead of N, (cgwiki to the rescue again here http://www.tokeru.com/cgwiki/index.php?title=HoudiniVex#Convert_N_to_Orient_with_dihedral)
vector dir = normalize(chv('../../cam1/t') - @P);
vector up = {0,1,0};
matrix3 m = maketransform(dir,up);
@orient = quaternion(m);
vector dir = normalize(chv('../../cam1/t') - @P);
vector up = {0,1,0};
matrix3 m = maketransform(dir,up);
@orient = quaternion(m);
Edited by AndyW - 2019年6月6日 10:43:14
Technical Discussion » Set normals to point at camera, VEX
- AndyW
- 336 posts
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I was just revisiting this too. It works for sure, but the local rotation around the z axis isn't ideal, so I'm looking at adding an up vector to fix that. I'm new to matrix transforms but I don't imagine it's too difficult
Technical Discussion » Set normals to point at camera, VEX
- AndyW
- 336 posts
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Technical Discussion » Set normals to point at camera, VEX
- AndyW
- 336 posts
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I've been using expression like this:
origin(“”,“../../cam1”, “TX”)-$TX
..in a point SOP to face normals in the direction of a camera, feels a little antiquated. Any tips on how I would go about this in VEX?
origin(“”,“../../cam1”, “TX”)-$TX
..in a point SOP to face normals in the direction of a camera, feels a little antiquated. Any tips on how I would go about this in VEX?
Technical Discussion » Import ABC point cloud in Maya
- AndyW
- 336 posts
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I've had the best luck importing Houdini particles via alembic into Maya into a VrayProxy, point attrs like Cd come in by default no need to run funky MEL scripts to access them
Technical Discussion » Recreating Copy and Transform for animation
- AndyW
- 336 posts
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That's very cool, and I tried something similar with merging transforms in a solver. In the attached file I've done a comparison with the copy and transform SOP and something I sort of hacked together with for-each using the loop increment as the offset in a timeshift, which provides a ton of control for smooth motion and offset but it doesn't accumulate the transforms relative to the previous copy the way Copy and Transform does
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Technical Discussion » Recreating Copy and Transform for animation
- AndyW
- 336 posts
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Basically I'd like to create an animating Copy and Transform to do infinite looping motion, I'm getting some interesting results with timeshift inside a For-Each loop, but it's not the same duplicated offset you get with the Copy and Transform SOP where the distance between copies multiplies with each copy, whereas with Timeshift inside a loop the distance is much more linear. I'm curious how others would go about doing this, maybe this is a job for a solver SOP? Any ideas? Thanks!
Edited by AndyW - 2019年5月22日 17:40:07
Technical Discussion » Animating "active" attribute inside SOP Solver
- AndyW
- 336 posts
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Technical Discussion » rendering packed prims with multiple shader assignments
- AndyW
- 336 posts
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In general I render cached geometry with delayed-load procedural for speed and IFD efficiency, material archives work fine for multiple material assignments on a single archive. My standard workflow has full geometry or sim caches in the lighting file for shader assignment and look dev. These caches are then re-cached and material archives are generated to be rendered as delayed-load archives on the farm. (I imagine there are ways to streamline these kinds of dependencies further with PDG, but that's a conversation for another time)
So I find myself re-caching geometry at times purely for the sake of material assignments and grouping. My question is pretty general, how are others going about this, and or are there better/newer ways to do this with packed prims instead of delayed-load?
So I find myself re-caching geometry at times purely for the sake of material assignments and grouping. My question is pretty general, how are others going about this, and or are there better/newer ways to do this with packed prims instead of delayed-load?
Technical Discussion » Grouping and active state on RBD sim
- AndyW
- 336 posts
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For what it's worth here's the fixed .hip file, Thanks Midassilver for the tips. Since I'm setting my active value with bounded grouping I didn't need to use the solver sop to accumulate color
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