On 10/25/2016 12:55 PM, Le_Forgeron wrote:
> Le 23/10/2016 à 17:05, William F Pokorny a écrit :
> You should also have a look at box uv_mapping... it's strange too.
>
> You can read it from the inside.
>
> I will investigate each object uv_mapping of hgpovray later, and might
> change it (in term of flipping).
>
> Target: being able to read the text on an image. The same image, on all
> objects
>
Yes, I ignored that mapping for being textures by face at least in terms 
of the cubic pattern(1) and I've always thought of the box uv/warp 
{cubic} mapping more in terms of what is needed for each pyramidal 
mapping of a face looking toward the origin. In other words I think 
about this mapping as if we have multiple sub-uv maps per box face.

That said, we could I think, get to where an image/pattern as viewed  on 
a plane would map more naturally onto the box as if wrapped in U like 
other patterns.

I'd say we take starting and ending mid face on the +X face out of 
consideration, but keep the idea of the map starting/ending on the +X 
face to better match our other maps. Are you then thinking of folding 
from +x backward for Y top/bottom using a map something like this?

Ymax
Xmax Zmax Xmin Zmin
Ymin

Suppose a significant amount box-uv/warp{cubic} mapping in scenes. Add 
an alternate box mapping? What is the complexity of another box mapping 
compared to mirroring in U(x) the pattern/image prior to 
box-uv_mapping/warp {cubic}...

Aside: I've used stand alone scripts & more recently a couple 
user_defined cameras for creating box uv/warp{ cubic } image maps(2).

Bill P.

(1) - I admit I've never used the cubic pattern other than by side 
effect in someone's scene file.

(2) - Partly aiming for flat image_map interpolation that works better 
through the box/cubic folds on the open edges of the mapping.

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