Hello everyone,

I’m currently exploring the idea of creating a 2d mouth Rig and would like to know if there’s any documentation or examples on how to use COPs in APEX.

I’m aiming for something similar to Blender's The MecaFace add-on, which makes it easy to add a Lego-style 2D face rig to objects. The idea is to have a simple 2D mouth rig that can be animated and swapped between different expressions directly in Houdini.

Any advice, documentation, or project examples to help me get started would be greatly appreciated!

Thanks in advance!

I just did something like that. i built a rig in sops (not using apex but that was a choice) basically on a flat plane and used cops to bring it into texture space to use it as 2d texture. This seems to be what The MecaFace addon does. One issue I faced was that cops doesn’t do antialiasing when rasterizing geometry which meant i had to rasterize in pretty high res and sample it down (which didn’t make it superfast)

ronald_a
I just did something like that. i built a rig in sops (not using apex but that was a choice) basically on a flat plane and used cops to bring it into texture space to use it as 2d texture. This seems to be what The MecaFace addon does. One issue I faced was that cops doesn’t do antialiasing when rasterizing geometry which meant i had to rasterize in pretty high res and sample it down (which didn’t make it superfast)

Thanks for the reply. I do see how I would do it in Cop's but what I'm trying to do it's more of, I want to see if it can be done in APEX. There are at least some nodes in APEX to apply/create a texture/material to the geo like sop::material and cop:: nodes but I really dont know how could I make it work.

Here's a quick try using the material_override attribute but I couldn't get Mantra to work so YMMV.

edward
Here's a quick try using the material_override attribute but I couldn't get Mantra to work so YMMV.

That is great thank you . I managed to get textures from an external copnet with your setup. Is there a way to use cop nodes directly from Apex, The APEX cop:: nodes are confusing to me I do not know to what I can connect them and how I could override the texture with them.

The cop:: APEX nodes aren't really designed for manual usage because they require special setups that are automatically done for slapcomp in the Solaris viewer.

I got Mantra working in this file. Seems like I can only do the material overrides properly when I use the shader in /shop

edward
The cop:: APEX nodes aren't really designed for manual usage because they require special setups that are automatically done for slapcomp in the Solaris viewer.

So would it be even possible to manipulate a texture with a controller on the rig, like on the photo(blender)?

Here's another attempt using an external COP network. To drive it, I output a "parms" detail attribute of the rig "control" that the COP network uses via the APEX Scene Invoke SOP. So it's a little bit clunky to set up. Also, it doesn't respond unless you're changing a value at a key and let go of the handle because that's the only time when the APEX Scene Animate will recook with the new value.

edward
Here's another attempt using an external COP network. To drive it, I output a "parms" detail attribute of the rig "control" that the COP network uses via the APEX Scene Invoke SOP. So it's a little bit clunky to set up. Also, it doesn't respond unless you're changing a value at a key and let go of the handle because that's the only time when the APEX Scene Animate will recook with the new value.

Thank you, that's exactly what I was looking for! 😊