I'm planning a small scene for Sketchfab that will include some vegetation, some objects and possibly one or two human characters.
For all I can remember Sketchfab has a limitation in terms of UV channels, maximum two, thus the altas method. Possibly one 2k or 4k texture containing all the vegetation and objets, and another one with just the characters.
[Now my issue]
One of the vegetation elements will be a palm tree. I've already crafted the procedural texture for the trunk, which is obviously a square.
This texture covers only one section of the trunk, the idea is to vertically tile it several times.
It would be extremely easy, if the trunk had its own UV tile to squander over (see attached image). Not the case.
How do I arrange the trunk on the UV tile so that its texture tiles only once horizontally and like 5-6 times vertically without taking over the whole atlas?
My idea is to cut the trunk (basically a cylinder) into several UV islands and overlap them all into a single square (diameter*3.14 to get the height of each section).
Would this be possible without incurring in awful UV seams?
I have already watched a (relatively old!) video about making atlases in Substance Designer, here
on Polycount's wiki, which was very illuminating AND quite shocking: he was EYEBALLING the UV layout!!!!!!!!
Maybe it's just my mild OCD speaking, but wouldn't it be better if one could place the UVs while relying on precise topological coordinates? Or is that how it's actually done, by (*shivers up my spine*) placing them "more or less in the right spot"?