The rgb4k_map.ppm and alpha4k_map.ppm

Houdini Integrated Plugin

Moderator: juanjgon

hubble
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Hello , can you tell me , how to use the two file "rgb4k_map.ppm"and"alpha4k_map.ppm", i render the particle which has Cd attribute ,but i can`t get the correctly result.
thanks
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juanjgon
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Hi,

Attached you have a couple of test scenes including particles and instances colored from the Cd attribute using these .ppm textures. Octane doesn't support custom attributes in the instances or particles yet, so the Octane plugin is using a trick to support at least a Cd type texture packing the attribute inside the UV map, information that is decoded texturing the particles or instances with the .ppm files.

Hope it helps,
-Juanjo
Attachments
2019-11-09 18_38_43-M__F-Octane_Houdini_development_HoudiniOctane_3.0_unit_tests_008-instancingCdCol.jpg
2019-11-09 18_38_29-M__F-Octane_Houdini_development_HoudiniOctane_3.0_unit_tests_008-particlesCdColo.jpg
2019-11-09 18_37_53-M__F-Octane_Houdini_development_HoudiniOctane_3.0_unit_tests_008-particlesCdColo.jpg
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juanjgon
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Location: Spain

The scenes ...

Thanks,
-Juanjo
Attachments
Desktop.zip
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hubble
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Thank you very much!
Fantasy
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Hi, I've been trying to get this this to work with no luck. I can read the Cd attribute when I render as particles but not with instanced geometry. I tried your files @juanjgon but your instance example doesn't work either, it just renders the instances black. Any suggestions on how I can get this to work would be appreciated.
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juanjgon
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The instances still need this workaround to render the Cd attribute. The scenes should work, but please, check the texture path set in the texture node, probably your .ppm textures aren't located in this same path.

Thanks,
-Juanjo
Fantasy
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Hi Juanjo, the .ppm texture is the right path, it works fine when I render as particles. But when I try to use instances (via an instance attribute) it doesn't work. Has anything changed with the build that would effect the instancing workflow!?
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juanjgon
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Weird! Here the scene attached previously in this topic works fine once you set the right path for the .ppm file. Are you sure that you are using the right texture from the plugin "tex" directory?

Thanks,
-Juanjo
Attachments
2021-01-18 12_12_13.jpg
Fantasy
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Thanks for your reply Juanjo. I worked out what it was, I was using the wrong texture node in the shader.
chocbot
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Hi Juanjo,

is there also a workaround available for using point attributes from the packed geo itself? For example I have a color attribute on a tree's leaves and that tree is instanced then. With that texture workaround it's only possible to get the color attribute per instance but not per point attribute of that instance, right?

Cheers
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