Vertex Colors workaround (standalone Octane)

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Vertex Colors workaround (standalone Octane)

Postby PolderAnimation » Tue Jul 10, 2018 7:39 am

PolderAnimation Tue Jul 10, 2018 7:39 am
*This example is for Octane Standalone and Houdini BUT the idea of mapping color to uvsets should work in all applications.*

When we where working on a project using Houdini we needed the vertex colors to go to Octane standalone.
Unfortunately octane does not support vertex colors so the first option was texture baking the whole sequence, but that was slow an not accurate enough.

Image

So we came up with a workaround that is faster and 100% accurate.
What we did:

We mapped the color to the height of a single uv sets.
We did this for the channels RGB (so a total of 3 us sets are used).
Apparently if you use a uv height of exactly 1 or 0 octane starts repeating the texture from the top so we scaled the uv grid a tiny bit that it will go from 0.005 to .995.

In Octane I multipled each color with a static ramp and then added them all together.

I attached my hip file and orbx.

Cheers,
Sander Kamermans
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vertexColors.rar
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Re: Vertex Colors workaround (standalone Octane)

Postby HMXMedia » Tue Nov 20, 2018 10:27 am

HMXMedia Tue Nov 20, 2018 10:27 am
Hi, good one :)
if you are interested , I've created a houdini script that only uses two Uv set (so you can still have your uv set 1 free).

_place the ramp folder at the same lication your hip file is.
_ select the object you want vertex color to be applied to
_run the python script (I'be placed it as a tool in a shelf )

limitation : right now you can only apply it selecting an ovject at a time.


link where I use it:
https://vimeo.com/301808706



Thanks !
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OctaneCd_To_UVs.rar
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Re: Vertex Colors workaround (standalone Octane)

Postby bloomendale_1 » Thu Nov 22, 2018 5:10 am

bloomendale_1 Thu Nov 22, 2018 5:10 am
i'm new to Octane, but i know it's very limited when you need to work with data.
In Houdini, you can just create rgb texture in COPs with one pixel per vertex/point of your geo, calculate corresponding uvs and sample that texture in shader right from the COPs without even saving it.
basically you can store all your attribs (float and vector) as COPs and sample them in shader using same uvs.
this approach uses only 2 floats in one uv set
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Re: Vertex Colors workaround (standalone Octane)

Postby juanjgon » Thu Nov 22, 2018 9:39 pm

juanjgon Thu Nov 22, 2018 9:39 pm
Without workarounds ... soon in Octane 2018.1 ;)

Thanks,
-Juanjo
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