Rendering Cd/Polypaint/VertexColor (not particles)

Forums: Rendering Cd/Polypaint/VertexColor (not particles)
Houdini Integrated Plugin

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Rendering Cd/Polypaint/VertexColor (not particles)

Postby limeforce » Sat Jul 30, 2016 5:23 pm

limeforce Sat Jul 30, 2016 5:23 pm
Hey! I noticed the posts talking about rendering the particle Cd attribute via packing it in a texture that is now provided with the plugin. I would like to use a similar workflow to render out points with Cd from arbitrary geo nodes and it seems totally doable, I'm just having slight trouble with what to plug where. I got it working for particles, one checkbox & texture assignment is simple enough. But for a polypainted mesh from ZBrush I only got part of the data to Octane via an Attrib Vop and it's mapped wrong as seen in the screenshots below. (Duh, a naive mapping from RGB-->UV leaves out the B component and the R & G values do not match what's in the texture). Any AttribVop/VEX trickery tips to solve this in the meantime until we get OSL and proper attribute support?

Next I could actually try just using three UV sets and alpha textures, that'll probably work but is inefficient and cumbersome.

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Last edited by limeforce on Wed Aug 03, 2016 9:18 am, edited 2 times in total.
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Re: Rendering Cd (not particles)

Postby limeforce » Wed Aug 03, 2016 7:50 am

limeforce Wed Aug 03, 2016 7:50 am
Hmm, for some reason I wanted to tackle the challenge of reverse-engineering the RGB > UV/texture > RGB packing that gives us the ability to render particles via a texture and make it usable for anything that uses Cd. Something that seems very simple to do is made a bit more complex due to inaccuracies in Octanes texture handling and in VOP/VEX precision. Or maybe I've just misunderstood something and chose the long hard way of doing things. Anyways, made some progress, just one weird artefact left.

I just have a creeping feeling that just when I'll be done spending X hours on cracking this, we'll get official support in form of either OSL or juanjgon magic, which will then obsolete my work. But I'm enjoying the math/eng workout either way :D

Scene file here (Houdini Indie) if someone wants to take a look:
https://dl.dropboxusercontent.com/u/300 ... ngCd.hiplc

If you want to render your polypainted/vertexpainted stuff with crazy banding artefacts you can just copy-paste /obj/geo1/subnet1/attribvop1 from my scene to yours and then in an Octane material (vopnet) use the texture rgb_4k_map.ppm that's in your OctaneForHoudini installation folder (as seen in my first post). I could maybe do a tutorial for that when I get this working properly.

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