On 3/12/23 10:30, Bald Eagle wrote:
> It's just the sign.  I was just wondering if the native implementation of the
> torus was "wrong", since I recall the uv-mapping being off compared to most
> other shapes.

You remember correctly. :-)

IIRC think we found the torus 'uv_mapping' reversed (handedness) 
compared to all other uv mapping in POV-Ray. It was for a short time 
corrected, but then restored to what it had been since v3.7 to maintain 
compatibility with old scenes. IIRC povr stuck with the corrected uv 
mapping - but that memory of mine might be wrong...

Aside: It's also true the new 'uv_mapping' added to additional shapes 
for v3.8/v4.0 was turned back off for other general 'uv_mapping' 
concerns. This is one place where our current v3.8 documentation does 
not align with the real state of v3.8 - the last I checked. In pulling 
back the newer 'uv_mapping' I 'think' povr  did too in the moment, 
thinking a fix would soon be adopted - but that never happened and I 
believe povr aligns with v3.8/v4.0.

Bill P.

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