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Technical Discussion » Why does Houdini export to .usdnc and not to .usd?
- jsmack
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Technical Discussion » what's the different between 9flt and 9flt(matrix)?
- jsmack
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Nodes that concatenate transforms will apply to ones tagged as matrix and ignore ones that are untagged.
Houdini Lounge » Attribute Wrangle make my spreadsheet non-editable.
- jsmack
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Technical Discussion » Scaling control for MTLX Triplanar Projection
- jsmack
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azes33
nice!!!..thanks a lot...and for rotate the triplanar?
There's a few different ways
chain a mtlxrotate3d for each axis of a euler rotation, or just one if you know the arbitrary axis you want.
mtlxtransformmatrix--3x3 signature is broken for me, but a 4x4 works. It's a pain to set the values from a euler though.
Define a space using a USD Coordys relationship and reference the space on the mtlxposition node.
Solaris and Karma » Export Camera .chan file transl. and rotation in solaris
- jsmack
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Have you tried lopimport camera to bring the camera into /obj and export it the usual way (with CHOPs)?
Houdini Indie and Apprentice » camera focus Distance - Troubles
- jsmack
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There's a parameter expression that can help--vtorigin(obj1, obj2) which gives the vector from one object to another. get the absolute value of the z axis from the result to get the focus distance.
edit:
the similar function origin would work as well since we only need one component:
abs(vtorigin(".", "TARGET")[2])
edit:
the similar function origin would work as well since we only need one component:
abs(origin(".", "TARGET", TZ))
Edited by jsmack - Feb. 12, 2023 13:18:27
Technical Discussion » View UV coordinates ?
- jsmack
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Solaris and Karma » Render Camera Slow to update but native cam is fast?
- jsmack
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This is most likely due to cooking a complex graph after the camera. Is your camera node being edited at the top of a long change of LOP nodes? This would trigger all of these nodes to recook when modifying the camera. For best performance, use a merge at the bottom of the chain to combine your scene, your lights, and your cameras. This way editing lights and cameras stays performant even with more complex scenes.
Solaris and Karma » MaterialX graph editor in solaris?
- jsmack
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Antti1999I don't think you can, since it's not represented as nodes in USD unlike MtlX
I'm new to Houdini in general and Python too.
When people make their own material managers how do they save selected nodes on a disk and then load it?
I was just experimenting with Houdini couple of days ago and tried to save some pretty complex material nodes with asCode() python function, but the generated code was enormous in size.
Is this the only way? Or correct way? I know this is off-topic and sorry
For a VOP Material Builder, right click and select Create Digital Asset to save as a new operator type.
Technical Discussion » Remove HDA from TAB search
- jsmack
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guilhermecasagrandijsmack
you could name the tool with untypeable characters to make it impossible to use type ahead filtering.
That would be my last resort, but I prefer a less hacky solution! haha.
I don't think there's anything you can do, since there is no search really. The type ahead filtering is applied the menu in which the tool is to appear.
Technical Discussion » Remove HDA from TAB search
- jsmack
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you could name the tool with untypeable characters to make it impossible to use type ahead filtering.
Technical Discussion » RGB values scale of 0-255 in Houdini?
- jsmack
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proceduralist
How to do colour matching in Houdini for colours being used in other apps? Is there a way the colour SOP allows values from 0-255 and reinterprets them from 0 to 1 equivalent?
The colors won't match anyway. Those values are for 8bit video space color, the values in Houdini and other CG apps are floating point linear color.
Technical Discussion » ChatGPT - Handle alignment script
- jsmack
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Technical Discussion » Camera Passepartout in Houdini
- jsmack
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Solaris and Karma » Karma Shadow Matte
- jsmack
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Tser
Thanks jsmack, I didn't think it was possible as I have spent quite a bit of time trying to achieve it, I thought that I was missing something, well here's to hoping this gets implemented soon.
T.
generating a backing plate from an hdri is pretty quick, if you want to use the existing features for now.
Solaris and Karma » Karma Ocio Color Transform not working
- jsmack
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Crustedink
do you know which role is used for a sdr 8bit renderoutput ?
None? I'm not aware of any such output handling. Ocio only handles input. To apply output transforms, use the command line oiiotool or ocioconvert.
Solaris and Karma » Karma Shadow Matte
- jsmack
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Tser
Thanks for the reply npetit, is there any way you could upload a simple scene comprising a Dome light with a hdr texture for lighting, a grid to capture the shadows (but is transparent) and a couple of objects casting shadows to replicate the image that I showed in a previous post.
Your expertise is greatly appreciated.
T.
It's not possible without rendering out the view of the hdr from that camera to use as a plate texture.
Solaris and Karma » Karma Shadow Matte
- jsmack
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brians
We have a background plate feature that somewhat fits what you're describing (ps: KarmaCPU only)
https://www.sidefx.com/docs/houdini/nodes/lop/backgroundplate.html [www.sidefx.com]
It sounds like this Arnold shader works a little differently, allowing for 'plateless' background plates by continuing the ray. Is that a possibility in the future of Karma (or possible now with some clever VEX in karma cpu)? When I investigated the background plate lop, it seemed like a lot of the composition stuff happens behind the scenes in Karma, and isn't just part of the shader.
Edited by jsmack - Feb. 7, 2023 15:46:40
Houdini Lounge » Still no alpha channel for transparent material
- jsmack
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briansjsmack
However, I don't want to see a simple 'transparency alpha' option, as the messaging is misleading as it legitimizes using it as such.
how about...
- a geometry property "refraction as alpha"?
- defaults to off
- when on, for paths that travel only through refractive bounces and then exit the scene, we track the final contribution, and then output that to alpha.
or does that still irk you John?
It doesn't bother me, but I feel like getting something that could be useful for a simple composite is more complex than tracking final contribution. It would also only be useful for parallel transparent planes where ray bending is mostly nil. I would aim for a single setting that would make the beauty pass 'compable' without artifacts such as doubled up transmission or ghosted internal reflections. How would fresnel be taken into account, or total internal reflection?
Solaris and Karma » Env light background alpha through glass / transmission
- jsmack
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tamte
now you mau need to do another render of just refracted white dome to get the contribution that will act like Alpha for stmap, so that you can unpremultiply it to cleaner values for mapping
and then scale back down before adding the rest
if you put solid color in the blue channel of the st map, you can skip having to do a separate render.
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