Dear NG,

No matter what I do it's really difficult to have the same render of
Terragen for my terrains in my Pov.. so I decided to try this trick on to
render my background in Terragen and the objects in Pov and then use Gimp
(my only photoeditor) to merge the background with the objects.

I am not yet very professional at this, so some advises would be much
appreciated. I try to but a lightsource exactly at the position of the sun
where it is declared in Terragen so that the shadows would be realistic
when I mix the images... Then I try to select part of my pov image by color
in Gimp and cut them and then put them in the background that I created in
Terragen. I am still feeling that I might get a bad work on this .. and
many will notice that the two images are made at different times. I was
looking for a way to find a script in Gimp that seperates the image and the
shadows into different layers for each image (by some color selection
method.. etc.) but I couldn't find one .. I think this functionality one
can find in photoshop..

I would of course just prefer to have all the image rendered in pov (after
some magical teragen-forrester combo to produce the pov).. but that's
really looks impossible (and I have limited time... I want to finish the
picture this month) as pov really doesn't produce the terrain scenes
exactly like that in Terragen.

Would appreciate any comments/advises/suggestions.

Sincerely,
Jose Capco

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Wasn't it ShiJie who wrote:
>Dear NG,
>
>No matter what I do it's really difficult to have the same render of
>Terragen for my terrains in my Pov.. so I decided to try this trick on to
>render my background in Terragen and the objects in Pov and then use Gimp
>(my only photoeditor) to merge the background with the objects.
>
>I am not yet very professional at this, so some advises would be much
>appreciated. I try to but a lightsource exactly at the position of the sun
>where it is declared in Terragen so that the shadows would be realistic
>when I mix the images... Then I try to select part of my pov image by color
>in Gimp and cut them and then put them in the background that I created in
>Terragen. I am still feeling that I might get a bad work on this .. and
>many will notice that the two images are made at different times. I was
>looking for a way to find a script in Gimp that seperates the image and the
>shadows into different layers for each image (by some color selection
>method.. etc.) but I couldn't find one .. I think this functionality one
>can find in photoshop..
>
>I would of course just prefer to have all the image rendered in pov (after
>some magical teragen-forrester combo to produce the pov).. but that's
>really looks impossible (and I have limited time... I want to finish the
>picture this month) as pov really doesn't produce the terrain scenes
>exactly like that in Terragen.
>
>Would appreciate any comments/advises/suggestions.


Rather than "selecting parts of your POV image by colour", wouldn't it
be easier to render your POV objects onto a transparent background.
[Ensure that your output file type supports transparency (e.g. PNG
format by using +FN) and add +UA to the command line to generate
transparency.]

The Gimp supports image transparency, so you just copy and paste your
pov objects onto your Terragen background image, where they appear as a
floating selection (just the opaque parts are selected) which you can
then drag into place. You can then drag the floating selection into
place and, if necessary, turn it into a separate layer.


Another different approach is to do your image compositing in POV. Paint
your Terragen image onto a backdrop as an image_map. You need to be
careful not to cast any shadows onto it, which can be achieved by
setting the backdrop to finish {ambient 1}. I believe that the tricks
used in the supplied incdemo/screen.pov can be used to accurately place
the backdrop object so that it exactly fills the POV screen.

-- 
Mike Williams
Gentleman of Leisure

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