Ignore Backface while projecting

felipefrango

So I'm baking normals and AO maps for a character I did in ZBrush and some of the parts were sculpted on meshes that are like a thin shell and when I put them in 3dsmax, outside and inside intersect and look really nasty:




What I'd like to know is if there anyway I can tell rays to ignore the inside faces when projecting details, I've looked everywhere and didn't find anything.

disanski

The same thing happen to me too. It is very annoying. The first time I got around by selecting all the inside faces that were sticking out and deleted them or just hide them temporary. If I can now when working on cloth I am trying to get away with one sided objects but most time it is not possible so I have to use the automasking function and select mask backface, but then I have to constantly turn it on and off which is slowing down the process. I would love to hear how do the rest of the folks handle this.

Kldn

Hi, you can use the option brush:automasking:backfacemasking. It disables backface sculpting.

felipefrango

Hm, how do you manage to select the inside faces? If I import them straight from ZBrush they're actually in a different polygroup already but usually I have to decimate them before importing in max and it merges everything into one group. I've tried selecting using the "by angle" threshold but since there are too many polygons defining the shape you don't have any sharp angles between them and it just selects everything even with a threshold of like 5.

It seems to me it's easier to just avoid shell'd shapes like this altogether or just cleaning up the bake but a feature for projection rays to ignore oppposing faces seems so simple to me I feel it has to be there somewhere.

disanski

It might be there, but I have not seen it. What I did is select one face from the once that are sticking out and just use grow selection and some manual selecting and deselecting to get it done. Not a lot of fun This I am sure you will get done once you start it, it is not so bad:). The question for me is what is the best way to avoid this and how are other people sculpting on top of thin meshes.

Mark Dygert

Two things I can think of;

1) is it just displaying it in the viewport incorrectly, because they're so close and you're zoomed out? Does it get better if you zoom in on a section or does it go away if you render a still shot?

2) Can you break the two pieces off in Zbrush (preferably around UV seams?) then export them as separate objects?

felipefrango

I'm at work right now so I'll check these things out when I get home, but yes, I believe it is viewport dependant, the amout of z-fighting/intercepting changes with zoom. I wouldn't mind but it's affecting the bakes. As for breaking the pieces in Zbrush I can't think of a way to do it cause the high poly sculpts have no UVs. Maybe if I paint/mask the back areas and create polygroups from that, I'll try it out when I get home.

Blake Mead

thanks a lot for the tip.