Am 31.05.2018 um 08:48 schrieb Thomas de Groot:

>> #declare MyTex =
>>     texture {
>>       image_pattern {
>>         png "My_pattern.png" gamma 1.0 use_alpha
>>         ....
>>         } // end of image_pattern
>>
>>       transform{TRA} // THE MAIN TRANSFORM HERE
>>
>>     texture_map {
>>         [0.0  texture{...} or pigment{...} etc
>>         transform{TRA inverse}
>>         ]
>>         [1.0 texture{...} or pigment...} etc
>>          transform{TRA inverse}
>>         ]
>>                 }
>>             }
>>
> 
> This is a bit different! What you do here is (1) transform the
> image_pattern, then, (2) and separately, inverse transform the
> texture_map. That will give something very different I believe. The
> transform should be moved down to the complete texture level, e.g.:
> 
> texture {
>   image_map {}
>   texture_map {
>     [0.0 texture {} transform {TRA inverse}]
>     [1.0 texture {} transform {TRA inverse}]
>   }
>   transform {TRA}
> }

To the best of my knowledge, there is effectively no difference between
the two constructs. I would consider the latter more intuitive though,
for the very same reason you'd expect them to differ in effect.

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