I've been doing a lot of NPR shading using illuminance loops and it's all fine and well until people want it to interact with PBR. A little research indicates it's not a trivial process to do anything beyond exporting cell shading as Ce for PBR. I think even the toon shading VOP does exactly that.
Other issues occur as well, including very bad sampling of area and geo lights. I mean I have something that works but with many caveats to consider. Illuminance lops and gather are my friends but I'd like to try something new
In the interest of making things more robust and having recently discovered https://www.sidefx.com/docs/houdini/vex/functions/cvex_bsdf.html [www.sidefx.com] I wondered if it was possible to build my own BSDF for cell shading? It seems feasible right?! (although I wonder why I can't find a cell shading BSDF example anywhere)
I don't imagine it is trivial although the documentation has clear examples of traditional models.
The other issue that's in the back of my mind is if Karma will be more limited and any custom BSDF work I do now might not make the migration.
I hope I can post a couple of examples later but it might not be allowed :/
