Normal Map Help

Rayvhen

To all who reply and take the time to read this, thank you very much.

What I'm currently having problems with is a pipeline to go from Maya to Zbrush and back to Maya after having done all my detail work. I'm quite comfortable with Maya and I'am aware of exporting as an .OBJ to make a ztool and then detail it etc. The problem I'm having is I currently have a medium poly character approx 50k tris and multiple meshes (armor pieces, helmet, weapons etc) how would I import this character into zbrush to create normal maps? Would I export each mesh seperately or as a single .obj? Should I have the entire character UV mapped before exporting and can I have multiple maps for my UVs? I know this is a lot to ask, so if anyone can point me in the direction of a tutorial video or the like it would be a huge help. Thanks again for your time. If it helps I can post the WIP character, but I'm kind of hoping for a universal method for this for future reference.

Wozner

You may export separate parts as .obj with UV information, and import them as separate subtools in zbrush, so you may have for example subtool for armor pieces, helmet and other things. It is always better to have differnt subtools in Zbrush

Rayvhen

Ok, so what about the initial UV maps? If I add multiple meshes to a single UV map for example helmet, chest armor, gauntlets on one map. When I detail them and create the normal maps individually will that cause a problem? Or would I have to compile the different maps in a program like PS before applying them to my low poly model in maya?

Rayvhen

If I'm not asking the right questions or I need to be more specific, by all means feel free to ask for more info. I know what I'm trying to do is possible, but I may be wording some of this incorrectly. Thanks again.

Seehr

There are multiple pipelines to follow up Rayvhen. For example, nowadays it seems very common that people directly sculpt the characters or whatever it is in Zbrush and then they make retopology for the High Poly sculpt in preferred software, then you create the UV map for the new topology and you bake the information from the sculpt as normal maps in it. You see this happening very often.

Then, as in your case, and many others, you could have also started modeling your base meshes in your preferred 3D Package, Maya in this case. As this was your chosen method, then i would personally recommend you to have already UV Mapped the whole thing and lay it properly, ready to export it for High Details. This way you will only need to import them in ZBrush, sculp, bake and get the maps.

There are tons of ways of doing things anyway. I have also seen people deciding to change the layout of the uvs or whatever after having sculped and you can follow some tricks to still get the information in the new uv layout.

Just tell me exactly whats your doubt about the workflow.

Rayvhen

Thanks for the response Seehr. My current hang up is I'm not exactly sure how to go about laying out my UVS. My personal limit for this is 2 x 2048 maps for his armor and cloth. So I'm just curious if I can just go ahead and layout the UVs as I normally would (for example armor and weapons on one map, soft surfaces on another), export each mesh as a separate .obj, do my detail work in zbrush then bring it back into maya and use the transfer maps method of baking my maps in maya? Going forward I definitely think I'll be starting my models in zbrush and breaking down the HP to LP from there. Thanks again.

After thought, when I import my high poly objects back into maya, can I just throw it back into the same scene that my character was initially modeled? Or do I need to start a new scene?

Seehr

2 x2048 maps sounds very good to handle a complete character. If you compare to for example Final Fantasy characters, as Lightning, they have 3 or 4 1024 maps. I personally always layout my UVs according to the material that the objects in the layout are going to have. It makes it easier later. But obviously you always run in the problem of optimization (if we are talking about videogames only, of course).

I also bake a lot of normal maps withing Maya's Transfer Map. It does a good job, not the best but pretty good for me. I just need to do some small cleanup later.

According to your doubt about how to export into zbrush, you can export the .obj entirely and then inside ZB split it, then export the pieces back outside to your scene, for example. Or you could also export every object individually, but this seems to be too much effort that you can avoid.

Im not a big fan of retopology. I find it to be twice as much work as you could do. But i do agree that when you start scuplting maybe you find yourself changing a lot the shape of your model and you do need some retopo.

And yes, if you export your.obj to ZB and then export the same object already sculpted, when you open it in Maya, it will be in the same position it was when you exported it before sculpt.

Rayvhen

You've been a great help so far, thank you very much. I am fairly new at zbrush so how would you go about isolating the seperate meshes in zbrush if I export the whole character as a single .obj? How do you normally go about baking your normal maps? Is it a separate program?

Seehr

Im glad to help as much as i can.
If you export everything as a single .obj with all uvs set and everything ready, you can open the subgroup palette and split into parts. if you export all this parts as single meshes later, they will still be in the correct position and have the correct uv information. Same would happen if you decided to merge them all back together in ZB after having worked the sculpt, but this doesn't seem to necessary and usually when you sculpt something in separate objects you want to keep them like that to have more control.

Important: Make sure your UV maps from different objects wont overlap. This will cause bad bakings and lot more problems.
I bake displacements and normals in two different ways: directly in Zbrush, or with Maya's Transfer Map tool. When i have done textures and i want to get Normals out of them, i use something like Bitmap2Material.

Rayvhen

Ok so basic rule of thumb is to make sure you have clean UV's that sounds pretty simple. One last question while I can think of it. How do you go about preserving your hard edges when you sub-d in zbrush? I'd rather not add holding geometry if possible.

Seehr

You can always crease your edges in maya or when you start subdividing in ZBrush just un-check the "Smooth" option. Cheers.