baking shadow maps for hair cards with alpha transparency

beartraps

I'm referencing the technique from Yibing Jiang's Siggraph course from Uncharted 4. Slides can be downloaded here: http://advances.realtimerendering.com/s2016/

On slide 45 you can see the technique: Basically bake an AO map from UVset 1 with alpha transparency onto UVset2 with cards fully laid out to get a shadow map.

Maya will not take into account the transparency, neither will Xnormal or any other bakers I know of other than 3DSMax. Had anyone had success doing this with Maya or any other bakers?

throttlekitty

I can't view the slides, but I can imagine the layout. How does their material setup compare to what you did? Normally, you'd plug the alpha bake into the transparency of a material and be done with it. When dealing with multiple uv sets, the specifics vary by program.

In Maya, use Windows>Relationship Editors>UV Linking, and UV-Centric. Here you can link a texture to an object(s) uv set as an override, to say "this texture should be active on this particuar uv set."

(i was going to post a pic, but my ISP seems to be having issues today)

Quick edit: I just realized your issue was in baking, i think. In the case of Maya, you can select a uv set to use in Transfer maps

radiancef0rge

You can use mentalray with deep occlusion or max with a complete map

beartraps

Just realized I had to use the batch bake function and assign a bake set for this instead of transfer maps. Seems to be working!

radiancef0rge

yay!

marks

If you use VRay make sure to bake CompleteMap and not LightingMap. Just throwing that out there.

beartraps

so at first this wasn't working in Maya even with Occlusion Deep, but then when I checked the box "bake alpha" and set the alpha mode to "surface transparency" it worked! Thanks so much radiancef0rage!