Is it possible to actually cull triangles on a mesh by doing it through the material by using an alpha? For instance if my character equips some boots that go up to his knee, can I point the base character material to an alpha and have it actually undraw the polys that are covered by the feet? I mean physically cull out the geo, not just alpha out that part of the foot. Thanks!
No (at least not that I am aware of). Although you can collapse all the geometry to a single point using WPO, which is effectively similar to not rendering it. You would need to make sure your feet vertices were not welded to the leg however.
we were doing this in 2010… … embarrassed i cant remember how.
Not how rendering works.
And double down, not how skeletal meshes work.
For something to cull the whole mesh has to be masked out.
Then theoretically, it won’t suck up a draw call to render which is essentially the same.
This is commonly used with world position to mask out meshes like Landscape Grass based on a render target. (If you set up right you can sample the target at a specific world location, so as to mask out the whole thing based on the object location).
For characters you need to go the Modular route.
If you don’t need the feet, you cut them off and use the shoe.
The part of the leg that potentially causes clipping is then usually masked out via material, or shrunk via WPO just enough for it not to clip.
As far as “how” you would do that…
The complicated way is to define a texture that allows the adjusting of the position of all the other pieces based on a standard - basically all clothing pieces share the same UV map.
This empowers you to be able to adjust all clothing based on all pieces equipped (add nodes to sum the textures up, and write to a render target that’s used in all materials).
Guess procedural mesh slice is also somewhat of an option… you could just slice off the feet
That not only is not how transparency works, it is also not how meshes work.