Bad Hair

General Discussion
1

Hello All.

I’ve been working on some simple hair consisting of multiple layers of geometry with a texture map applied. The layered geomery is all part of the same object. It kind of works but I am still getting what looks to be sorting artifacts that I can’t seem to get rid of.

darksim.com/w/bad_hair.png

hair = loader.loadModel(ANDY_HAIR)
hair.setPos(0.0, 0.0, 0.0)
hair.setScale(*GLOBAL_SCALE)
hair.reparentTo(self.model_pivot)

I have set things up this way.

hair.setDepthWrite(False)
hair.setAttrib(DepthTestAttrib.make(DepthTestAttrib.MLessEqual))
hair.setTransparency(TransparencyAttrib.MAlpha)
hair.setBin(‘fixed’, 0)

And have also tried it this way.

#hair.setTransparency(True)
#hair.setBin(‘fixed’, 0)
#hair.setDepthTest(True)
#hair.setDepthWrite(False)

I have also tried including alpha { ms }
in the egg file.

I’m missing something, just not sure what. Any help would be much appreciated.

2

http://www.panda3d.org/manual/index.php/Transparency_and_Blending there is a long part about depth-sorting in there. multisample should be the best option available.

3

Yes, I read through that, but enabling multiple-sample in the egg file does not seem to help. ms mode seems to threshold my texture transparency so that an alpha above a certain value is fully opaque and below fully transparent.

Upon rereading that section, I wondered if ms mode was falling back to M_binary for some reason. I changed my config to multisamples 16 and that fixes the thresholding. I still have those artifacts, unfortunately.

One thing I don’t understand is that when I make it double-sided (setTwoSided(True)) it looks worse…large portions of the outer layer of hair become transparent as if the polygons are single sided and the normal is facing the wrong way.

4

OK, figured out what the problem was. The hair geometry was created in Maya as a bunch of layered “plates” which were then then combined into a single piece of geometry. Somebody else is doing the modelling on this project and I don’t really know my way around Maya very well but, when I started separating the geometry and testing pieces, it worked.

So, if I “separate” the hair geometry, select all, and then export it from Maya it works. Now I just have the expected multi-layer transparency issues to deal with :slight_smile: