View Full Version : Simple Skin issues

09-20-2010, 02:04 PM
I've been working on a character's head model and used the simple skin node to render the skin, wich i think turned out rather well. But unfortunately there is one problem area that i can't seem to get rid of. And that is the area around his eyes. You can actually see thru the skin there. I attached 2 pictures to show what i mean... :help:

So please tell me, how can i get rid of this? I've tried different settings in the simple skin node. And the eyesocket is closed just like the rest of the head model. The slow rendering doesn't really help testing and doing previews either. :question:

09-20-2010, 03:13 PM
Yes... this is because the eyball itself it protuding inside the "volume" of the skin itself. its a tricky one to get around, having to model the inside of the eylid so as it doesnt intersect the eyeball... especially once you get into deforming it.

The only fix I ever found is to reduce the depth used in simple skin to near 0 in this area, you can use a weightmap, or texture to isolate the area. Since the eyelids rarely, if ever receive backlighting, it shouldnt produce a noticable difference, and so the frontal scattering should still look good.

Someone posted a thing a while back, where they were using a surface thickness based gradient to drive simple skins depth parameters... id thought that may be helpful here too, but havent gotten round to trying it out thus far.

09-20-2010, 04:40 PM
Im think Matt created a pdf of lee-perry-smith work , which had a work around for this issue

09-20-2010, 04:44 PM
Dowload Lee files and check the nodes. http://www.newtek.com/forums/showthread.php?t=105896
He uses an "internal" occlusion preprocess to guide the thickness of the skin. So that situations like that don't happen, like in the ears.

09-21-2010, 01:02 AM
Thanks for your replies guys! I will look into the thickness node trick and the weightmap solution from rebelhill later today when i get back home from work. Thanks!:thumbsup:

09-21-2010, 01:05 AM
Thickness doesn't work, since it's Z axis camera dependent. Either a weight map, a texture map or Lee nodes.

09-21-2010, 02:20 AM
Thickness doesn't work, since it's Z axis camera dependent. Either a weight map, a texture map or Lee nodes.

Yes, sorry i meant the lee nodes solution. Thanks.