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View Full Version : Surface Baking Catmull Clark SubD Model



mattadamson
12-24-2007, 06:58 AM
Does anyone know the best way to surface bake a catmull clark subD model ?

Any info or help would be great :D

Thanks!

mattadamson
12-24-2007, 07:15 AM
Thought I best elaborate a bit more on this

I am having a problem with UVs and surface baking when using catmull clark.

Firstly when I am in catmull clark mode, when I add UVs the UV window only displays points, not polys.

Secondly when I Try and surface bake the model in layout using Surface Bake Camera the UVs show as if they are not subD and are all square edged.

IMI
12-24-2007, 01:25 PM
Well, your UV map is essentially just points. The polys can be seen and selected with regular, non sub-patched models, but they have no bearing on the UV map itself. It's the points which are the UV coordinates, and any textures are interpolated on those polygons, between the points.
The reason you're getting a jagged map is because you have a lo-res mesh underneath that subpatch. When you subpatch, you're not really adding more points to the model, just smoothing it all out in between - unless you freeze it, then all those "virtual" points become real points.
So, your texture map that's made when you bake it is representing those actual points.
At least that sounds plausible to me. :D
I don't ever UV map anything in subpatch - I freeze the mesh first, since most of the models I make are for exporting for other programs.

mattadamson
12-24-2007, 01:48 PM
Hey thanks for your reply! :D

I tried freezing the mesh but when you freeze the model the UV map squares off like a subD model with subD tuned off :S

Any idea on that?

gerry_g
12-24-2007, 04:14 PM
LW does not support interpolated uv's for CC only linear, Modo will bake interpolated uv's for sub patch objects with n-gons (Modo doesn't actually use CC's but because it uses n-gons will import them and convert them to standard subs + n-gons). But if you intend to reimport to LW you'll have seam problems as interpolation is as already stated not supported. The best yo can do is use linear subs which kind of sucks, but thats life.

mattadamson
12-24-2007, 05:28 PM
Hey thanks for taking the time to respond!

I think I understand most of that.

I have a total model built in CC mode with edge sharpness set, does this mean I cant UV it and I will have to start over an build it in regular SubD mode? Theres no way to UV it within LW?

Cageman
12-24-2007, 06:01 PM
Ok.. so it's apparently a lacking feature, not necessarily a bug then. Oh well...

As I see it, if your bakingresults are dependent on UV-map being interpolated I have to say, no... can't be done in LW. Kind of sucks... What if you freeze the object and tripple all polygons being n-gons and then turn that object into a SubPatch object? :) I imagine the polycount would be high though.. ?

gerry_g
12-24-2007, 06:07 PM
Not rebuild it as such just regularize the n-gons within the model by making them into quads, then linterpolated uv's for regular subs will become available to you, cuz as you've already found out with CC's whether your mesh is interpolated or frozen makes no difference all you get is linear uv's. Modo does work properly as a rout if you intend to freeze your CC mesh and won't give seam errors on reimport (I think the 301 demo is up and available now) but is no good if you need to keep as live CC subs.

Beat me to it Cageman, oh well two replies are better than one

Cageman
12-24-2007, 06:08 PM
Ok.. it may be worth a try what I just wrote... However, one thing to do before freezing the CC-object. Press 'o' and set the Catmul-Clark level to '0' or '1' (well, as low as you can, really). Freeze it and fix all N-gons and do some work with merging polys and spinning quads, whatever. Then set your object to SubPatch instead. Could work...

mattadamson
12-24-2007, 07:14 PM
Thanks so much to both of you for your help so far! :)

I will give this a go tomorrow evening once xmas is over and report back!