ZBrushCentral

Weird bump map problems

ZBrush Usage Questions
#1

I’m having little problems with my bump map, that I’m painting for my t-rex. Here’s the start in zbrush. It looks pretty much right.

But when I render it in 3ds max, problems start to occur. [img]http://img174.imageshack.us/img174/8935/3dsmaxhn5.jpg[/img] Notice how there's weird corners on the map right above the arm. It looks blocky and somehow lowres. Why's that?

Another weird thing is that the bump map seems to be inverted on the leg. There’s holes instead of bumps. Look what happens when I invert the map in MAX.

Now the bumps on the leg look right, but on the torso they are inverted. What could cause this? Very annoying and mysterious.

Thanks for all help!

#2

actually, to me, the whole bump map appears to be going in instead of out.
in maya, you adjust using the bump depth. if it’s the same in 3dmax, then if the bump is a positive number, make it negative.
just a thought.

#3

In which image? In the last one the map is inverted, in the second one it is not. So one of them should look right, but both of them look wrong :smiley: Very very weird. Please help me!

#4

What is happening is that the bump is flipping direction when the UV’s cross a seam. This is something I’ve often seen happen with Max. I can’t recall if anyone has ever posted a solution.

#5

Now that sounds like a nice little bug :smiley: Has this problem been discussed here in some thread, so that I could find a solution?

What about the other issue? Why does the bump map come out as if I had painted it in sudiv.level 1, although I painted it in subdiv.level 3? It has thease stupid corners everywhere.

#6

As I said, I can’t recall that anyone has ever posted a solution. The problem lies in how Max is reading the map. That’s not a ZBrush error.

Regarding your other issue, you might try turning on Tool>Geometry>Suv when you divide your mesh. This will smooth the UV’s while it also smooths the model. For most circumstances, you don’t want that wich is why it’s turned off by default. But yours may be one of the cases where it is desirable.

#7

Try using mental ray if you’re rendering in scanline… scanline has various problems that aren’t worth messing with.