On 4/3/25 11:37, Bald Eagle wrote:
> When I was making my tori last night, I was trying to capture that pinkish color
> that you have there.
> 
> Of course that's the part you snipped out . . .
> 
> What's the special sauce?

The trick was, at least partly, there in my post:

...
union {
     ...
     texture{
         pigment{ color rgb<1,1,1>}
         finish { emission <0.1,0,0> phong 0.5}  // <--- Here, emission
     }
     ...
}

However, you must also run with a v3.8 or later(*) release and set the 
version to 3.8 with a #version directive or ini / command line flag like 
+mv3.8.

V3.8 is needed because, with it, the default finish{}'s ambient value is 
always zero.

A better answer requires more, if I get back to that work, the detail 
should be in its own thread. For now, see the asides below.

(*) Lying. Radiosity sets ambient to zero in earlier versions - and 
users could always set it to zero.

---

Aside 1: Relatively late in the overall v3.8 development cycle, the 
ambient default value was changed from <0.1,0.1,0.1> to <0,0,0>, mostly 
based on the argument v3.7 and v3.8 renders of old scenes looked washed 
out due the gamma handling changes. These changes made the old ambient 
grey far too strong - because it wasn't, itself, gamma adjusted.

For me, the best reason for the v3.8 ambient <0,0,0> default, over - for 
example - a new srgb-space, gamma corrected one, is that any non-zero, 
grey value has always worked against per feature color support in 
POV-Ray.

---

Aside 2: With respect to quality renders, I believe we under-utilize the 
per feature / aspect, color functionality already in POV-Ray(*). 
Further, that with 'minor-ish' modifications, expanded, per feature, 
color functionality can be added /exploited.

(*) We often use single values for 3D color vector specifications. Or we 
think of and treat density{} as a single value proposition, when it's 
effectively a pigment{}.

Some years ago ('povr named fork' days), I merged existing, but 
variously named and, sometimes, mostly forgotten color control 
capabilities in POV-Ray under a single new 'amplify' color multiplier 
keyword. I went on to extended 'amplify' to additional features in 
today's yuqk fork.

Going to stop here. I find - and oddly enjoy - that so much with our 
POV-Ray play requires books to describe well! :-)

Bill P.

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