Ok. That explains why my RGB manipulations had no effect
when importing grayscale heigthmaps.

But is it really correct to ignore the forumula completely
for grayscale images. As I see it this formula is the only
way to scale the import to a correct heigth when importing,
or is there any other way to do that?.

Here is an example:

Lets say we have designed a grayscale heightmap 1024x1024
with a max heigth (RGB=255,255,255) of 50 meters.

When I import this into MED i will get a terrain with the
dimension 1024x1024 quants and a heigth of 512 quants.

This means that I now have a terrain of 1024x1024 with
a height of 512 meters instead of the desired 50 (assuming
1 meter = 1 quant )

This would be easly solved by having the RGB formula active
for grayscale heigthmaps also. Lets say the formula would
scale the imported heigth by the R-factor. In this case we
would import with 'z-position' = R*(50/1024) + G*0 + B*0.

Then the imported terrain would become
1024x1024 quants but with a height of 50 quants
( same number of faces though)

Well .. this was just a thought.
Anyhow I now understand that the RGB formula has
no effect for grayscale images as those from Terragen and L3DT.

Thank's
~Roland