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Technical Discussion » How to import a USD asset with material to SOP?
- jsmack
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Not really, no it's not possible. The materials in USD don't exist in the scene and aren't always representative of materials that can be used in /obj. As for if the textures could be procedurally extracted from usd materials, it's possible but probably not worth the trouble.
Solaris and Karma » LOP lights to OBJ?
- jsmack
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No tooling for that, but you can use the lop import object to fetch a transform, and use python expressions to drive parameters on the parented light. good luck with that usd python api though, what a nightmare.
Solaris and Karma » normal maps with subsurface scattering using materialx?
- jsmack
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ChristopherRutledgemestela
Shouldn't all these envvars be exposed as parms on the karma lop?
I could imagine wanting to set this per project or even per shot. It'll get frustrating if we have to keep jumping out to shells or the windows envvar editor to alter these xpu specific settings.
big +1 to this. hopefully these things will largely be exposed once we're out of beta?
How would it be exposed though? If it was a primvar on the rendersettings, they you'll see the texture resolution jump around if you display different parts of the graph, potentially requiring a renderer restart and full texture flush every time you move the flag around. That sounds not ideal.
The other way would be as a flag for husk, but then it won't have any effect when rendering interactively. it's not like rendering with a rop where the endpoint is the same no matter what.
An env var seems like the only way to globally control the setting without causing inconsistency within a session.
Solaris and Karma » triplanar map materialx
- jsmack
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Piledriver
i don't have any scale node with triplanar
what are you talking about? There is no scale node. read my posts, use a multiply node to scale the position space. this is really just basic shader building. position multiplied by 2 is twice as many repeats of the pattern per unit of space.
Technical Discussion » About color Picker (ACES)
- jsmack
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dyts
Enivob
On the color picker, make sure you have color correction enabled. It's the sloping icon on the right.
it's checked
That thing doesn't work at all. It seems like it applies the forward gamma conversion no matter what direction the picker is going in. I end up with a value that's double or triple gamma corrected instead of the inversed linear value. I did, however, figure out how to at least pick colors without any correction so that it can be converted in Houdini using ocio convert nodes. Disable the color correction 'gamma icon' on the color picker, then set the picker space to 'ignore colorspace'. this will allow picking screen colors as-is, but they still need to be converted to linear or acescg.
I usually read the image in COPs and use ocio transform nodes to convert from the input space to ACES, then read the values off the viewer with the inspector mode.
Technical Discussion » PC frequently crashes when left to render Karma scenes
- jsmack
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Siavash Tehrani
Another thing you could try is alternately disabling your Optix (GPU) and Embree (CPU) devices to see if it's one or the other causing issues. Take a look at the Disabling devices section at the bottom: https://www.sidefx.com/docs/houdini/solaris/karma_xpu.html [www.sidefx.com]
this is the first thing I would try.
Disabling XMP would also be something to do, remember that XMP is overclocking. Not sure if it's applicable to threadripper, but disabling PBO should also be done to rule that out.
Solaris and Karma » triplanar map materialx
- jsmack
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Piledriver
what i need to multiply with? i never used mantra but with the triplanar node withprincipel shader its just easier to do that
the amount you want to scale it by. Scale = multiply
Solaris and Karma » normal maps with subsurface scattering using materialx?
- jsmack
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tarincamarena
Normal maps don't seem to be working at all with subsurface scattering using materialx standard surface material in Houdini 19.5.303. I thought I saw in the demo video for Houdini 19.5 a Capybara with subsurface and normal maps using mtlx in xpu. I cant get the normal maps to work with subsurface scattering at all using cpu or xpu.
normal maps don't affect subsurface scattering. Since the scattering is determined by raytracing inside the surface, normal maps won't have any effect. They will affect fresnel blending and the specular term though, which is what you see with the principled shader.
Solaris and Karma » triplanar map materialx
- jsmack
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Piledriver
the coordsys it's my issue now i don't just unrderstand how name the attribute to make the scale work to triplanar node, i mean at the staart of this conversation the issue itself it was about the fact that i can't scale or rotate the texture for triplanar, about rotating i solved that putting a mtlxrotate node but for the scale there isn't a node to allow that, but just i give up because i'm tired, so just i don't use materialx for triplanar mapping. maybe in future when this are done better i could do that but i don't want become crazy to make something where other render engine just do in a easier way
scale is even easier, just use the multiply node. Same as with Mantra shaders.
Solaris and Karma » triplanar map materialx
- jsmack
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Piledriver
i tried to check the help if you mean the doc its not so clear.... hope in future sidefx implement better this triplanar because in other render engines and also with principled shader its a lot simpler
what are you having trouble with? The coordsys or the triplanar texture? The coordsys is by no means required for the triplanar texture, it's just a convenient way to transform it. As for enriching the features of the node itself, since it comes from MaterialX, it would be up to them to adopt a more complex node. Alternatively, sidefx could implement a karma-specific node, but there would have to be significant demand for that.
It's also not impossible to just build your own triplanar projection yourself based on the math used by the mantra version.
Solaris and Karma » normal maps with subsurface scattering using materialx?
- jsmack
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I'm not sure what you mean. Normal maps can be used with the standard surface in MaterialX, but the effect of the normal on subsurface is minimal. The VEX subsurface bsdf in for karma doesn't take normal as an input, so it probably doesn't take normal into account under mtlx either.
Solaris and Karma » triplanar map materialx
- jsmack
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Piledriver
i open the scene but i don't understand why don't work i create the new one USD Coordys node
It's pretty picky about hierarchy, I had to experiment a bit. Check out the help and example file under the coordsys node.
Piledriver
this coordinate system node work only for cpu
Oh, bummer. I forgot about that limitation. For XPU, there's always multiply and add nodes.
Edited by jsmack - Aug. 1, 2022 00:28:37
Solaris and Karma » triplanar map materialx
- jsmack
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The USD Coordsys can be used to place 3d or 2d textures, which can also be used with the triplanar projection node. The triplanar projection node doesn't allow for a different projection for each texture though, so this may not be what you are after.
Technical Discussion » Quaternion precision problem?
- jsmack
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Well, it's using float math, what do you expect? You would need infinite precision to get exactly 0. Make transform gets around this by special casing since it takes degrees as input.
Solaris and Karma » complexity option at usdrender rop
- jsmack
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Setting complexity to "Very High" should automatically add gack/nernies/greebles to your model
Houdini Indie and Apprentice » Group question
- jsmack
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BabaJ
But because Houdinis' scene viewport can be so flaky at times(in many different ways), the selection doesn't always show up at all.
baloney, I'm familiar with bugs in the viewport, but that's not one of them.
Technical Discussion » Does H19.5 Karma XPU run with AMD GPUs?
- jsmack
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Karma XPU uses an Nvidia specific raytracing library, so it won't ever work on AMD unless Houdini adds a different raytracing engine that's cross platform.
Technical Discussion » OCIO/ACES - Color Picker Ignoring Color Spaces
- jsmack
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The numerical values are always passed as-is to the underlying parameter. The color space conversions are only for the eyedropper sampling of screen pixels. I know it seems like it should convert input since it says right there, 'input space', but that has no effect that I've seen.
Solaris and Karma » Karma Pixel aspect ratio for 19.5 doesn't work
- jsmack
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AhmedHindyjsmack
Karma ROP in out context, or usdrender LOP node? I think there's a bug in resolution on the ROP that should be fixed in the current daily build.
The USDrender LOP and also the same for the Karma ROP.
Hmm, well it works fine for me.
Solaris and Karma » MaterialX + String path attributes?
- jsmack
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dhemberg
I'm curious if I shouldn't expect this to work, and whether there might be some workaround that didn't previously exist that would allow XPU to work this way?
I wouldn't expect that to work.
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