Im trying to make a smiley face sphere for a friend. Im using an image
map. The problem is that his eyes are spaced too far apart. And well his
face looks a little distorted in general. Is it possible to scale that
image map or do I have to draw it right in photoshop? Ive tried putting
the scaling in various spots. I cant find it in the documentation.
Besides I want a little insight into how image mapping works.
Drew

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You could look here and save some trouble and learn a new trick:

http://members.xoom.com/POVRAY3/procedural.html

But since you also want a little info on image_mapping, here goes.  I'll
just cover planar mapping.

Since a planar map always starts as a 1 unit wide image projected along the
Z-axis, starting at 0 and extending to Y = 0 and X = 0:

(y)
1
^-------------
|                     |
|                     |
|                     |
0rigin --------> 1  (x)

You probably want to start by centering it on the origin:

translate <-.5, -.5, 0>

Then comes any scaling.  Just make it the size of the object you are placing
it on or maybe a little larger.  Then you can rotate it to line up anyway
you want without worrying about it moving out of place.  Then translate it
and the center will be at the vector you specify, since you centered it to
begin with.

The best tip is to use square images!  That way you don't have to worry
about any lateral distortion, since the image always starts as a square in
POV, whether it was made that way or not.

Another helpful thing to know is that if you use a mask in the paint program
and then save as tga, the transparency will be saved.  This is a very useful
feature.

Hope I provided some insight into image mapping. :)

-Mike

Drew wrote:

> Im trying to make a smiley face sphere for a friend. Im using an image
> map. The problem is that his eyes are spaced too far apart. And well his
> face looks a little distorted in general. Is it possible to scale that
> image map or do I have to draw it right in photoshop? Ive tried putting
> the scaling in various spots. I cant find it in the documentation.
> Besides I want a little insight into how image mapping works.
> Drew

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Mike wrote:

> You could look here and save some trouble and learn a new trick:
>
> http://members.xoom.com/POVRAY3/procedural.html
>
> But since you also want a little info on image_mapping, here goes.  I'll
> just cover planar mapping.
>
> Since a planar map always starts as a 1 unit wide image projected along the
> Z-axis, starting at 0 and extending to Y = 0 and X = 0:

The above should read:

Since a planar map always starts as a 1 unit wide image
projected along the Z-axis, starting at 0 and extending to Y = 1 and X = 1:

Ken Tyler

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That was a pretty bad mistake on my part.  Thanks for the correction.

-Mike

Ken wrote:

> > Since a planar map always starts as a 1 unit wide image projected along the
> > Z-axis, starting at 0 and extending to Y = 0 and X = 0:
>
> The above should read:
>
> Since a planar map always starts as a 1 unit wide image
> projected along the Z-axis, starting at 0 and extending to Y = 1 and X = 1:
>
>

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