Subject:
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Re: "Illusions"
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Newsgroups:
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lugnet.cad.ray
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Date:
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Wed, 3 Mar 2004 11:15:35 GMT
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Viewed:
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1863 times
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In lugnet.cad.ray, Mike Thorn wrote:
> The only code I changed was for Color57, here:
>
> #ifndef (Color57)
> #declare Color57 = #if (version >= 3.1) material { #end texture {
> pigment { [rgbt < 1,0.4,0,.8 >] #if (QUAL > 1) filter 0.85 #end }
> finish { ambient AMB diffuse DIF }
> #if (QUAL > 1)
> finish { phong 0.5 phong_size_ 40 reflection 0.2 }
> #if (version >= 3.1) #else finish { refraction 1 ior 1.25 } #end
> #if (BUMPS) normal { BUMPNORMAL } #end
> #end
> } #if (version >= 3.1) #if (QUAL > 1) interior { ior 1.25 } #end } #end
> #end
I've played around with this a bit and I think what is happening is that you're
trying to accomplish several things at once, and some collide with others.
By setting the transparency and transmit values high, you're bascially
instructing the program to "make the parts more transparent" (as in "let more
light through") and "tint the light passing through them more". It's either one
or the other. In a real life situation, an almost transparent tinted glass would
certainly not tint the light passing through it more. And the other way around
is also true: if a tinted window "tints" the light a lot, then it is not very
transparent.
(This is not 100% accurate, see further down for more on it)
Because 3D CGI *DOES NOT WORK LIKE REAL LIFE MOST OF THE TIME* (the number one
pitfall for most users, in my opinion), what POVray does with both tranparency
and filter values is (I think) something pretty unrealistic: either deduct (or
invert) the original color ... or potentially simply grab any other available
light and multuply it up to compensate for the loss of the original color. (The
documentation says that with a .9 transmit value, only 10% of the original color
is retained).
Now, let's go back to the transparency / tinted light issue. If what you're
trying to edo is change the "tint" in the the light passing through while at the
same time maintaining transparency levels, the way to accomplish this is to
change the *color* definition of the see-through material - by making it darker
or lighter.
So that's basically my interpretation. In the link below you'll find a POVray
file with a bunch of balls with material definitions based on the one you
provided.
(BTW, the refraction values might also be adding to the confussion)
http://miguelagullo.net/technicpuppy/misc/filter.pov
Disclaimer: I could be completely off-base here ...
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Message has 2 Replies:
 | | Re: "Illusions"
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| (...) Looking at your file made me notice something that tells me definitely that you and David are correct. I never noticed before that there is a filter value in there after the rgb vector. Naturally that would skew things a bit. So David was (...) (21 years ago, 3-Mar-04, to lugnet.cad.ray, FTX)
| | | Re: More Transparency issues (was: "Illusions")
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| Here I am again, pleading for help. I wonder if I'll ever learn enough that I can stop having to ask simple questions... This time the part won't show up, rather than the part showing up, um, *too* well. I'm working with that transparent sceptre (...) (21 years ago, 4-Mar-04, to lugnet.cad.ray)
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Message is in Reply To:
| | Re: "Illusions"
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| (...) No, I was editing the properties of the transparent color using Transmit. The only code I changed was for Color57, here: #ifndef (Color57) #declare Color57 = #if (version >= 3.1) material { #end texture { pigment { [rgbt < 1,0.4,0,.8 >] #if (...) (21 years ago, 2-Mar-04, to lugnet.cad.ray)
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