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Organize UV shells of multiple subtools inside Zbrush

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#1

I have model with seperate subtools. Each subtools have their UVs.

Is there any way to organize the UV shells of multiple subtools inside Zbrush? Basically the shells are scattered around or are overlapping each other in a single UV tile. I want to be able to rearrange and organize them in this single UV tile so that I can bake out map that has these UV shells in a single patch/map.

I can flatten a subtool in UV Master and scale rotate, etc. Then, I try to select the 2nd subtool and flatten it but somewhere along the process I mess and I cant unflatten them. Is there a workflow that handles this situation inside Zbrush. I am hoping to avoid exporting all these as OBJs and rearrange them in Maya and then bring them back in and project details.

#2

Ok, seems like if I use Morph UV to flatten them and rearrange or scale/rotate them it works. The only issue here is I have no idea where the UV tile bounding lines are. Morph UV does display a grid but it is not the exact size of a single UV tile or space as seen in Maya. Looks like a bit of guess work is required. :frowning: Any advice is greatly appreciated.

#3

How to edit your UVs inside of zBrush :

First, I think for now ZBrush isn’t really made for UV tweaking. Most of people use GoZ to send the mesh to another soft for UV fine adjustment. Maybe in some subsequent zBrush version UV editing tools will get improved. But, you can still use zBrush to edit your UVs, with the help of UVMaster, which in my opinion is the most kick ass automatic UV unwarping tool out here. Automatic unwarping, but what fewer people know of is that it also enables you to edit your UVs inside of zBrush.

Let’s start with the beginning, trying to use “morph UVs” like you did (I think it would be everybody first guess to try that) :
When you use morph UVs to get the correct boundaries you should set the grid size to 1 and click on snap to axis to make sure it is centered. However I did test it by superimposing two snapshots, one from zBrush with those settings and one in maya, and I’ve noticed there is some little mismatch along the top border. So doing it with morph UVs isn’t worth nothing, it’s maybe just useful to quickly check your UVs but not really precisely. Moreover : when in morph UVs, when you select some UV by masking the others, for example along a seam, it will always select all the affected vertex. You can’t move them separately. And anyway even that is totally useless as when you exit morph uvs the changes are reverted, so you can’t change your UVs at all with the [Morph UVs] way.

Solution : Use UVMaster (located in your plugin palette).
In UVMaster, press the [Flatten] button. If it is grayed out, just unpress [Symmetry] and get rid of your upper subdivision levels (or you can press [work on clone], that will make a temporary copy of your mesh so you can edit its UVs and then copy/paste them from your temp mesh to the original one - safer and easy as copy and paste, literally :wink: ).
Then it will give you your UVs laid out correctly with the correct grid settings already there for you. (I made the screenshot matching comparison too to be sure and it passed).
You can then use move/transpose to edit your UVs, each is editable separately even if it is affecting multiple vertex, and changes are kept. Tadaaaaaa !!!

All that makes me remember something : I think that way you can even send to photoshop with zAppLink and paint directly on your UVs and make it picked up as a texture (yes I mean a real texture, not polypaint). I have to check on that again as it sure can be useful.

One last thing : If you’ve got multiple subtools which share the same texture (with shells laid to use a single UV space) you should read about Multi Map Exporter which can export those joined textures for you. It can even work with multiple UV tiles like mari or mudbox (the mudbox Uxx_Vxx format and 1001, 1002… in mari).

Hope you’ll find that useful !!!

Cheers from belgium :slight_smile:

#4

KeuPon, thanks a lot! I will try out your recommendations. Will get back to you when I am done with this!!! Thanks a lot!!! :smiley:

#5

Perfect, copying and pasting UVs worked. Always knew about this process but completely forgot about it. I just exported all subtools as OBJs in their lowest subdivisions. Organized all the shells to my liking in Maya’s UV editor. Saved the objects as OBJs again. Imported these OBJs (which now has the updated and organized uv shells in a single UV space) into Zbrush. Made sure the original (which had the disorganized shells) were all in their lowest subd. Then simply copied updated UV shells from the imported subtools and pasted them onto the orignal subtools. Voila! Painless, and sure as hell beats projecting details from old mesh to new ones >_<

Thanks for the helpful advice :+1: