Render pplastic material using mesh vertex attributes stored in a .PLY 3D model

[ZhaoJinyu96]

• [❔ other question]

Summary

I can use a texture to set spatially varying diffuse albedos of 'pplastic' material, but I wonder whether the diffuse albedo can be assigned spatially using the color of vertices stored in .ply 3D models.

System configuration

• Platform: Windows
• Compiled variants:
  • scalar_rgb
  • scalar_spectral
  • scalar_rgb_polarized
  • scalar_mono_polarized
  • scalar_spectral_polarized

Description

I used your sample code of 'bsdf_pplastic.xml', and changed the uniform albedo to a texture.
I also tried to set the albedo according to the vertex color stored in the .ply model but it says that
unreferenced object MeshAttribute[
[xml.cpp:1059] name = "vertex_color",
[xml.cpp:1059] scale = "1"
[xml.cpp:1059] ] (within bsdf of type "pplastic")
Is there something wrong or 'pplastic' does not support MeshAttribute plugin?

bsdf_pplastic.zip

[tizian]

Could you please post the full version of your test scene that also includes your matpreview.xml file and the .ply mesh?

Also, do you observe the same problem with a simpler diffuse BSDF (without any polarization)?

[ZhaoJinyu96]

This is the full version of my test scene (I modified docs/scenes/bsdf_pplastic.xml).
sample.zip

I had no problem when I used diffuse BSDF.

[tizian]

Ah ok, I see what is happening now. It's a combination of two things:

• The diffuse color argument of the pplastic plugin is actually called diffuse_reflectance (instead of only reflectance in the diffuse BSDF)
• The mesh_attribute texture does not implement the mean function that is used during importance sampling of the pplastic. To work around that, you can go into pplastic.cpp and adjust the parameters_changed function:

void parameters_changed(const std::vector<std::string> &/*keys*/ = {}) override {
    m_specular_sampling_weight = 0.5f;
}

[ZhaoJinyu96]

Thank you very much! The problem is solved.

[tizian]

Great :)