Jonathan Mack

KaleWeaver
I get the impression that Mantra is getting reduced support for the newer updates.

Correct, mantra is on maintenance--it's not being removed but won't get new feature support like loading textures from the new composite network. It works with the old composite network though.

I've submitted issues with respect to Karma and barycentric only interpolation. I'm not sure what the reason of the limitation was, but it didn't seem likely the limitation would go away.

Flagging the surface as a catrom subdivision interpolated surface does resolve the issue but will smooth the surface and change the shape slightly, and cannot be used with all topologies so isn't a perfect work around.

KaleWeaver
The docs page that discusses primitive spaces indicates:

"non-convex quads will usually still be treated as bilinear patches"

This help document is Mantra specific and doesn't mention how Karma treats surfaces. Karma is closer to the viewport in the way it interpolates attributes, using barycentric interpolation of triangles rather than bilinear patches.

Mantra is still a quad-native renderer and does bilinear interpolation if you don't mind giving up gpu rendering and materialx shaders and usd support. It's still an excellent renderer.

pixelninja
I'm not a fan of tying FOV to aspect ratio. Unless you mean the aperture aspect ratio and not resolution aspect ratio.

yes, aperture aspect ratio--fov as a derived property of screen size. pixel resolution is a render property independent of the camera.