An old trick was to take a polygon hair prop with a higher transparency/alpha then make a duplicate, maybe scale it up a fraction, offset it bit and then you could get a thicker final mesh to render. This gave me the idea to make a simple new plugin to Thicken out the results of the simulations. It might also give a more realistic render and rely less upon painting in the layers of hair into the texture map.
For the Thicken beta version 0.1 I’ve allowed for a single additional layer with a surface offset, xyz displacement and a scaling factor. I’ll probably be adding a second layer and second column of settings. I don’t think I’ll add multiple layers because that will make for a very tricky UI. I’ve also considered giving the layers their own shading domain but I’m not sure if that is safe yet – Carrara can cope with it when you add and remove them in the vertex modeller so it should be possible.
The Thicken plugin can of course be used to conveniently add a surface offset or indent a mesh by telling it to hide the original mesh.
I used it in the render of this cloth hair simulation. There are only a few artefacts where the layers of hair went through each other, before the thickening was applied – you can see these on the left shoulder. This next attempt at dynamic cloth hair used twice as many layers as the last one, with 5 down the side of the head and two more at the back. The self collisions performed nearly perfectly but it took more than 12 hours to run when draping over the figure in a 5 second animation sequence. I also improved the alpha map technique by using 2 pixel thick strokes to paint the tips of the hair.