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View Full Version : Fast Skin for a light fixture?



IMI
10-21-2008, 12:48 PM
(See attached picture)

This is a bathroom vanity light I modeled and I'm trying to get that SSS/glow effect in the fixture globes. I figured the Fast Skin material would be about the best way towards that, and the results are more or less what I was wanting, with the major exception that in reality the glow would be more in the center, with the edges being darker - the light bulbs sit in the middle, so when seen head on, the glow would appear to be more centered.
No matter what settings I've tried for the Fast Skin, I keep getting this same effect - the edges are brighter than the center. it's not a bad effect down low in the globes, but I can't seem to penetrate that darker band around the middle without blowing the whole thing out completely.

Does anyone know of a way I could get what I want? I'm thinking maybe weight maps, but I wonder if there's a better way using just the nodes? I'm not real familiar with how the math functions work.

BTW, the light source is actually two spherical lights placed where the bulbs would be, with a weak distant light in front to brighten it up a bit. Ignore the other materials - I knew my biggest problem was going to be the globes so that's where I started, and the rest is just something I slapped on as I try to decide if I want a chrome look or a brass look or whatever else.

Thanks. :)

*Pete*
10-21-2008, 02:21 PM
i followed your shameless OT link...

im no expert with the new materials so i will follow any tips that come up...

what i would try would be to have a very short light fallof.

another thing i think contributes to the dark band is that it seems as the glass is thicker there, if the light is placed lower than the band then it will have more glass to penetrate..try to raise the light to the center of the thick part and play with fallof to get a result you like.

IMI
10-21-2008, 02:39 PM
another thing i think contributes to the dark band is that it seems as the glass is thicker there...


Oh Jeez! Yeah, you're right. :foreheads
I can't believe after several hours of modeling and rendering I hadn't even noticed that. And even as I was beveling it inwards I was trying to make sure I kept it uniform thickness. Somewhere something went wrong. My LightWave must have malfunctioned - surely *I* couldn't make such a dumb mistake or overlook anything so obvious. Yeah, that's what it was, Modeler malfunctioned. ;)

Well, thanks for noticing that Pete - I've fixed it and even my first test was much better. That was, in fact, the entire problem - the thickness. I was so sure the integrity of my model was right, it never occurred to me to check it out again in wireframe.

Chalk up another one for the value of getting a fresh eye in on something. :thumbsup:

IMI
10-21-2008, 03:32 PM
Somewhat better.
I adjusted the Fast Skin distances a little, added some falloff to the spherical lights and of course, thinned out the thicker parts of the globes. Much closer to what I wanted - now I can get on with finishing the rest of the thing.

POTO2220
10-23-2008, 09:24 AM
you still have lighting troubles....the light would not hit the wall that hot with the sconce glass diffusing it...especially those kinds of sconces that are very opaque yet translucent....may I ask what your setting are for this surface? from your diffuse to spec to transparancy to translucency?? they look nicely shaded/textured, but the light is passing through them in a strange way. also, more light would be dispersed out the top, giving a much brighter spot and falloff moving up the wall...the whole point for these types of fixtures.

IMI
10-23-2008, 10:15 AM
Yeah, as I said, I was just concerned with getting that translucent glow first - the material. I hadn't even begun working on the lighting problems yet, just wanted to get the more difficult surfacing out of the way first.

A Mejias
10-23-2008, 02:50 PM
Maybe try a light object with luminus polys and turn on caustics.

*Pete*
10-25-2008, 12:25 PM
And even as I was beveling it inwards I was trying to make sure I kept it uniform thickness.

get the thickener plugin.

bevel only the exterior shape, delete the disc you bevelled with, use thickener and set thickness...works perfect, even with complicated shapes.

IMI
10-26-2008, 02:51 AM
get the thickener plugin.

bevel only the exterior shape, delete the disc you bevelled with, use thickener and set thickness...works perfect, even with complicated shapes.

You mean THIS (http://www.flay.com/GetDetail.cfm?ID=1540)? The link to the plugin comes up 404 Not Found.
Or [probably] THIS (http://www.blochi.com/gfx/thickener_en.html)?
I tried that one just now and got some strange results - the "thickening" was being done unevenly. Maybe something in LW 9.5 broke it, maybe it doesn't play nice with 64 bit (although I can't see any reason for an lscript to need either 32 or 64 bit), but it didn't do what I expected to see on a test object.

I appreciate the help, but honestly, whenever I want to thicken anything I just take it into modo. Same thing with just about any kind of edge manipulation or UV mapping... and lots of other things Modeler could stand to have built-in. ;)