Unfortunately, if you try ro create tileable textures in Zbrush the usual way, you’ll run unavoidable into troubles.
So I finally did some exploratory experiments to find out where exactly these problems come from and to show that there are bugs.
For this test I work with a doc size of 100 x 100 cause so the effects could be better seen on the screenshots. But the problems are exactly the same with any resolution.
Okay, let’s go:
First I created a doc in 100 x 100 and filled it with flat white.
And I set the document background color to green and the gradient range to zero. Why, we will see later!
I placed a 45° rotated quad in the middle with 50% flat gray.
Inside I placed a sphere with a white ToyPlastic material.
I did this to show that flat colors won’t be affected by the problems we’ll run into later.
Now we can already see that ZBrushes canvas size is wrong.
Precisely we miss two lines on the top and one line at the bottom.
We export our doc, open it in Photoshop and this confirmes our suspicion.
Here the missing lines are back but unfortunately dark grey (R44,G44,B44) only.
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Okay, we come to the conclusion that we have here two problems.
The first one is, that the canvas don’t show the complete doc content, two lines on the top and one line on the bottom are missing.
But that problem could be by-passed by extending the canvas before export and then cut off the overlapp. But it’s nevertheless a poor mark that this would be necessary and I hope this will be fixed in future versions.
The second bug that causes the artifacts on the edges of the canvas is more serious and I have now idea how to avoid it.
Okay, you could export the doc with some other offsets (before or in this case even totally without enlarging the doc size) and repair the odd parts and seams in Photoshop, but this isn’t a serious workflow and at the moment, it looks like there is no easy way to create 100% clean tileable textures out of Zbrush with this technique.
I really hope this gets fixed!
Kind regards,
Tom