ZBrushCentral

Question: Baking Shadows/Details into Textures

ZBrush Usage Questions
#1

Hello! I’ve only just recently downloaded the trial version of ZBrush 3.1, and I’ve been tinkering around with it for the past week or so. It’s very impressive! I’m still learning the ropes, though.

I’ve already made a few things, including this modest little mushroom:

shroom.jpg

As you can see, it has lots of bumpy goodness to it, but I haven’t painted any texture onto it just yet. This picture was taken at subdivision level 5, though, and I want to export the model at its lowest subdivision level (level 1) into a game. In order to retain the details, I want to bake the shadows I see here into the texture that I’m going to make for the mushroom, but I’m not sure how to go about doing it.

I understand that you can just use projection master to place the shadows into the texture map. But this method seems to have a problem in that when you rotate the mushroom, the shadows and highlights completely change. If I rotate the mushroom 180 degrees to work on the opposite side, I’ll be presented with a completely different configuration of shadows and highlights. It’s as though I can rotate the object, but the lighting setup stays put. How am I supposed to bake the same shadows and highlights into a texture that covers the entire mushroom when I can’t even view the mushroom from more than one side without completely changing the way those shadows and highlights look?

All I want to do is set up some lighting on the object in ZBrush so that its shading looks similar to how it’s going to appear in the game, and then bake those shadows into my (soon to be created) texture so that I can retain this bumpy goodness at a much lower polygon count. How do I do this? There must be a way, but I’ve had a hard time finding info on the web or in the ZBrush help files that teaches me what I need to know, and none of what I’ve found so far has been terribly helpful.

Please point me in the right direction here! Thank you so much for your help.

#2

What you really want to do is create a displacement or normal map. Exactly which depends on the rendering engine that will be used. The directions for how to do so are found in the online documentation. See my signature.

#3

Thank you for the response! Unfortunately, the game I’m going to be importing it into is Second Life, which doesn’t really allow bump or displacement maps.

#4

Hmm. In this case you could create a cavity map that you could then use in Photoshop to combine with your color map via one of the layer modes.

In 3.1 you’d use ZMapper to create the cavity map. In 3.5 you would be able to do it natively by creating a cavity mask that you then convert to an alpha. 3.5 also allows you to create an ambient occlusion map which could also be combined with the color and cavity maps for an even better final texture map.

#5

Thanks! I read about ZMapper and tried doing what you suggested. I also tried a few other little things which aren’t really worth mentioning, but I’ve learned quite a bit. It’s a shame you can’t create an “ambient occlusion map” in 3.1 in the same way you can create a cavity map with ZMapper. I suppose I’ll have to read bout how they do it in 3.5.

I tried to come up with some sort of interesting texture to put on the mushroom, and I got the following results:

shrooms.jpg

I wasn’t going for anything particularly realistic, but I’m still pretty disappointed with the results. It’s not your fault, though; I just need some serious practice in making textures, that’s all. The second one from the left is the one where I tried using your cavity map method. The rest are just me playing around on my own, and I tried to salvage my wildly colored texture by making the one on the left look more like a piece of candy…

Thanks again for your help.