To make this worse, the way Blender’s current margin packing code is implemented makes it impossible to predict what the margins around your islands will be or assure that a minimum margin is kept to prevent mipmapping problems.
stability and uv baking. That is all I like from ptex in a blender pipeline. Not even gonna use cycles. I wanna use it for texturing. The idea of having a version of a texture that has none of the flaws a UV map introduces is very nice. After unwrapping you can then compare- see where the uv is causing regressions.
And yeah, the creative momentum. It makes the difference between a completed project and an abandoned project some times.
How many models do you have abandoned at the UV unwrapping stage? Or they are unwrapped but not textured, because the unwrapping killed the momentum.
Would be nice if cycles supported it, but hey that is an extra. If you can export it to other render engines, you are still sorted.
This is a very valid remark. Margin should be in pixels, not some abstract factor.
+1 to margins being in pixels. The only problem with that is that often when unwrapping and packing islands it’s done before an image is loaded. Therefore, there’s no frame of reference for number of pixels vs. distance.
As for UV unwrapping killing momentum, I can’t say I’ve ever experienced that. UV unwrap is usually a 10 minute operation for me, tops. If they need retweaking later I can do that, but I tend to be thinking of exactly how I’ll unwrap to get detail where I need it while I’m working anyway.
The main advantage of Ptex (except for the no-UV’s part) is that you can dynamically scale up the texture resolution for parts of your mesh where you need more detail. It is kinda like the dynamic topology of texture painting.
And it is absolutely not useless even if you are not going to use a supported render engine in the end. Baking your results to a quick UV-map is really simple.
Its even worse then this. The meaning of that abstract factor depends on which unwrapping/packing tool you use and is usually also influenced by the (unwrapped) size of your UV islands. See my long post to the devel list last March [1].
In my opinion the Lightmap packing algorithm is the only one in Blender that gets margins “right”. Its margins are specified as a percentage of the texture area so if you know you will be using a 4k texture it is easy to calculate how many pixels wide your margins will be, even if an image hasn’t been loaded yet.
[1] http://lists.blender.org/pipermail/bf-committers/2013-March/039547.html