I agree with you one the centering of image_maps, since that what everyone
tends to do anyway before applying any tranformations. (ie. translate <-.5,
-.5, 0>).  Same deal with height_fields.

The other thing you bring up is a little more complicated.  I don't think it
would be easy to have an image apply to only one part of an object.  That
would be handled better with parametric mapping, but that would mean having
to create a UV space for all primitives.  For a sphere that should be simple
enough, since that's pretty much covered by spherical mapping anyway.  A box
would have to be split up a bit.  Cylinder even harder.  Sor...hmm.

Maybe it could happen someday.

-Mike



Ken wrote:

> Greetings !
>
> Half question half feature change request !
>
>    Of all the features in Pov-Ray there is one that has properties
> that make little sense when compared to the operations of other
> features. This would be of course the image_map & and height_field
> location.
>    Why is it when everything else is centered at origin these have
> been implemented to start at origin and go to x1 y1 ? There is no
> other feature, outside of the media feature and radiosity, that I
> can think of, that causes more confusion for new users and old,
> than this aggravating quirk.
>    Would it have been difficult to have had the image automatically
> centered ? I think this behavior should be changed in Pov-Ray release
> 4.0 if at possible. It sure would ease the suffering of millions.
>
>    Another problem for many users has been the fact that image maps
> act on a solid object the same as a pigment and or texture. That is
> if applied to one side of an object it appears reversed on the opposite
> side of the object. Perhaps it is time to implement a new option to the
> image map feature to allow something like a hollow statement. This would
>
> allow application of an image map to a single surface and not the entire
>
> object. Handy for that beer bottle label, ship decal, and so on.
>
> Comments and discussion encouraged.
>
> Ken Tyler

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