Overlapping UV's, Tiling textures, AO baking, HOW!?!

Soul_of_Solace

Ok, so is there a process by which one can create an asset that has tiling textures, AO baking and even overlapping/organized UV's?

It's a workflow I've yet to figure out. Which is why most of my work is mainly just plain complete UV unwraps with no tiling textures or UV's that overlap (since such things have always ruined AO baking). I've always figured you can only do one or the other and not a combination of them.

Pola

Probably depends on the model I guess, You can have overlapping UV's and offset the overlaps -1 in UV space for anything you bake, but if thats not producing the AO details you want, I think you can bake AO into your vertex colour or you could use two UV sets, one for tilng and another for unique detail.

cptSwing

There are a couple of ways you could include AO into tiling assets.. the 'pricier' way would be to use a second, unique texture layout and multiply an AO map over your tiling texture. Alternatively, look into baking AO into the vertex colors of your mesh - how good this looks will depend on the number of verts you have, though.

Soul_of_Solace

Hmm, are there tutorials for such things? I don't think I can recall needing to bake vertex colors out (what purpose does baking vertex colors serve again?) for any assets. And how do you "multiply" an AO map over the tiling texture? My first thought was in photoshop but that made no sense. I suppose that's an option in a game engine like Unreal somewhere?

Eric Chadwick

You use a 2nd UV set for the AO texture, that has no tiling. Similar to the way you do a UV for light mapping. You can overlap UVs if you are smart about reuse, but not very much. Many of the newer engines these days do dynamic AO as well, so no need for a dedicated texture.

Some methods here.
http://wiki.polycount.com/AmbientOcclusionMap

cptSwing

the Wiki is your friend: http://wiki.polycount.com/AmbientOcclusionVertexColor

as for UDK, yeah you'd need to muck around with the material editor and load up your second uv set, assign both diff & AO textures, and multiply the two before piping them into the diffuse slot (from the top of my head)

Snader

Like cptSwing says, use several UV unwraps. One for the tiling maps, and one for the AO.

edit: seems like this has already been clarified while I was idling.

Soul_of_Solace

I'm still trying to wrap my head around the idea of having UV's dedicated to tiling textures share the same 0 to 1 space as UV's that will be textured the regular way through a diffuse texture. The diffuse texture would have a lot of empty space if that were the case no?

cptSwing

You need two UV unwraps basically, one in channel 0, one in channel 1 (and possibly another actually, for lightmapping).. note that this comes at a cost to performance - more vertices if i am not mistaken, plus your second AO texture.

Soul_of_Solace

In Maya, I've had to copy UV's into a second UV set in the past for more "unique" pipelines. Is it something similar to that? Like, would the UV's for the tiling textures exist on that second UV set by themselves?

Eric Chadwick wrote: »

You use a 2nd UV set for the AO texture, that has no tiling. Similar to the way you do a UV for light mapping. You can overlap UVs if you are smart about reuse, but not very much.

It sounds like what he was saying here. Although, I guess that means you'll need to spend more time to create an entirely new UV set just for the AO.

Pola

Its really up to you what works best in your situation and what your chosen engine can do, if it can handle realtime AO then you don't need to bother about the extra uv set/unwrap for an AO map, likewise if you bake AO into vertex colour, however as mentioned above the quality of that type of AO may not be what you are after depending on the density and spread of your verts on the model.

If you make a unique unwrap, you are not limited to just using it for AO if you wanted to add some unique details you could mix those in as well with the tiling diffuse. If your are just using AO you can place the AO in the alpha channel of the tiling texture to save space or save it out at a lower resolution.

To create a new uv set in maya, open the uv editor and click the polygons menu, near the top is create empty uv set, click the option box if you want to give it a specific name. On the right end of the menu's is a menu called uv sets, click this to toggle between the different uv sets. Just toggle to that uv set when you do projections/etc to edit/unwrap uv's for that set.

Soul_of_Solace

I typically like to bake out an AO map via Batch Bake (Occlusion) in Maya to have something I can Multiply layer on top of my diffuse texture in Photoshop as a means of adding in detail. I guess I'd need to figure out a way to see if I can retain this method through the usage of a secondary UV set. Although, not sure how that would work since the two UV sets would obviously be quite different.

Soul_of_Solace

Is there a tutorial that shows baking the AO into Vertex Color in Maya? I looked at the Wiki but it had a link to a digitaltutor site that wasn't working for me. I've only used Batch Bake to generate an Occlusion Map for use in Photoshop.

Pola

Did you try googling something like "Ambient Occlusion Vertex Maya"? Can probably find a written tutorial or one on youtube about it. The AO from a 2nd uv set can still be applied as multiply onto your model that gets diffuse from tiling uv set. You just need to do this with your shader setup.

Wonkey

Soul_of_Solace wrote: »

Is there a tutorial that shows baking the AO into Vertex Color in Maya?

If I remember right, this guy did it: Gnomon Environment Modeling for Games with Nate Stephens The DVD costs a bit, but it is worth it. He shows lots of great tips. It is done in Maya, but very convertable and revelant to Max as well.

Soul_of_Solace

Wonkey wrote: »

If I remember right, this guy did it: Gnomon Environment Modeling for Games with Nate Stephens The DVD costs a bit, but it is worth it. He shows lots of great tips. It is done in Maya, but very convertable and revelant to Max as well.

Thanks a bunch! I'll definitely check that one out. I still need to wrap my head around baking to the vertexes, if that information (the bake) then exists with the model itself and is not dependent on any shader/texture info.