Hi;

This question goes out to those who are already familiar with the Metahuman plugin for Houdini.

When you create a MH via the "Metahuman Character Rig" node, enable "Import Textures" and "Animated Maps" then make the HDA editable and dive inside, you can see the rig logic that deals with everything from the body/facial rig setup to how the animated maps are controlled via Apex Rig Logic.



Inside the "mh_anim_shader" matnet, there's a MatX subnet named "head_shader_am" in which an extensive setup that deals with the animated wrinkle diffuse and normal maps. The maps are multiplied via "Subnet connector" parameters that are promoted up at Material level. I could be way off, but I believe that the rig logic looks for corresponding blendshape values and then correlates their values with these promoted subnet inputs so that when a facial CTRL slider is manipulated and a certain blendshape gradually becomes active, so does its corresponding subnet input parameter value thus creating animated wrinkle maps.





My aim was to adapt this Matx based setup to its Octane counterpart. So I copied the entire setup, minus the shader into an Octane Material Vop. But since this is a vopnet, it does not promote subnet parameters, only Shader parameters. So, even though I named the Octane Vop "mh_anim_shader", its promoted shader parameters can not be invoked through the Apex rig logic, and the attempt failed

Is there a direct or indirect solution to this, what do you think? Are MatX Subnetworks and Material vops inherently different from one another altogether?

Any help/suggestions or ideas are highly welcome.

Lotsa cheers;

AJ

Quick google says that Octane should already support MaterialX? https://docs.otoy.com/standaloneSE/MaterialX.html [docs.otoy.com] ... So I would expect that the plugin would translate this appropriately for rendering without you needing to do anything extra.

If you really need to substitute the material, you'd need to make sure that the material assignment of the geometry inside the "mh_material_anim" is pointing at your new material. First test is to see if any textures come through at all. Inside the APEX rig, the mh_logic node will output the material_override attribute with the appropriate texture blending value that gets used by the material. I'm not sure whether the Octane plugin properly supports the material_override attribute, it might not.