Forum: Carrara


Subject: physics lab (aka light and shadows)

nomuse opened this issue on Oct 05, 2003 ยท 4 posts


nomuse posted Sun, 05 October 2003 at 5:00 AM

After reading previous set of posts I decided to check how a fully clothed DAZ figure imported. I screen-shot all the steps and I might be able to generate a tutorial. As seems to be common experience the textures were automatic but the transparencies weren't. After noting that transmaps looked fine in direct light but lousy in indirect (aka GI) illumination, I made the above test. These are two identical spheres, identically textured, each with a spot light aimed at it. As you can see, Skylight is enabled as is "Light through transparency." The sphere on the right is inside a much larger, fully transparent sphere, with no other material channels and "no light interactions when fully transparent" checked in the materials. Note the result. The spot light shines through the transparency without difficulty. However, the sky light is stopped dead. This may seem like a little issue. But imagine the effect when GI rendering is applied to a Poser figure with transmapped hair, brows, and lashes, and transparent eyeballs. Incidently, with "Visible" unchecked in the assemble room, light does get through...but dimly! C3, Mac OS.

nomuse posted Sun, 05 October 2003 at 5:27 AM

I believe I found the trick. In render options, ALSO check "indirect light." (Not just "Skylight.") The spheres now appear identical. And I can't wait to give my DAZ figures their eyebrows back!


mateo_sancarlos posted Sun, 05 October 2003 at 2:18 PM

Yes, always enable indirect light and leave photon mapping off for final GI render. I'd like to see your screenshots of how to handle transparency on imported Poser figures. Several people here have indicated they would do this, but the only guy I know who actually did it is toad (http://www.castironflamingo.com/tutorial/index.html).


nomuse posted Sun, 05 October 2003 at 3:03 PM

I'll see if I can cobble something up (I was meaning to do another tute some day). The settings are pretty straightforward; same parametric, multi-channel shader as the texture maps, but... Carrara uses white as transparent and black as solid, and the "no light interactions" seems to happen only at true white -- which does not occur on many JPEGs. What I got working used two "Shader Ops" modifiers; Invert and Stretch, the latter set to increase the brightness of the whites slightly. For some reason I didn't trust "invert color" on the map itself, and I'm not completely sure of the function of "white is invisible." I need to run the lab a little longer! I'm also toying with making a multichannel mixer channel to hold the base texture, with the part-specific channels only active to adjust lip gloss and similar. It should be easier to scroll through and to make changes in...but as far as I can tell it has to be set up from scratch. Final test image was a single figure lit from over the shoulder in a single spot, "glare" enabled to "blow out" the highlights slightly, face lit only by indirect light generated by default sky setting. Lovely effect....and something that NEVER worked right in Bryce, at least not for me.