ZBrushCentral

edges over 90 degree angle

ZBrush Usage Questions
#1

Hey all, I am fairly new to ZBrush. I created a model that I rather like, but my low poly has many areas where faces are at a 90 degree or more angle to each other. I discovered that this is a problem as soon as I exported my normal maps and tested them in 3D Max. On the problem faces the lighting for the normal map is all jacked up. After reading through a few tutorials, I discovered that having 90 degree angles is a big no no. My question is, what’s the best way to fix that? I want to keep my model as low poly as possible, and adding bevels all over the place doesn’t seem like the right answer to me.

I noticed that the normal maps themselves had the strange lighting bake right into them. So my question is, would it work to add more geo to the low rez to get a good normal bake, then remove the beveled edges? Do people usually go into Photoshop and adjust the normal maps there to fix the issue? Or do most people just add bevels all over their low poly model?

Any suggestions with this would be much appreciated, thanks!

#2

It is usually a combination of both. Beveled edges that are later removed, as well as touch-ups in photoshop. As a rule of thumb, if a 45-60 degree smoothing angle in your 3d App doesn’t create a smooth transition, then then a normal will not either.

A lot of people will also generate an object spaced map, then convert that to a tangent spaced map using xNormal, or something of the like. This will generate a better result most of the time. But not always. Other people will use a displacement map and convert that to a normal map. It all depends on what the result you’re looking for is, and then you must adjust your work flow to help achieve the look and feel you want. In regards to hard edges using Zmapper I suggest running some tests on a box with a couple of extrusions off of the surface. See if you can get the look and feel with quick tests and learn what workflow is best suited to your needs. Then apply that workflow to your actual model.

#3

Hey goast666, thanks a lot for the info! It hadn’t even occurred to me to try creating an object space or displacement map and convert it to a tangent map. I will definitely try that stuff.

Thanks again for the reply!