Bump/Normal Map smaller than texture map

[danielj]

I wondering if is it worth to use smaller bump/normal map than the base texture.For example,the biggest normal map for the Moon is 4k,so if I use it with a 8k or 16k texture,it seem a little strange.I have to choose between bigger resolution and sense of depth.But why no one ever did a 8k or 16k bump/normal map of the Moon?
I was experimenting this with Iapetus.I put t00fri??s 4k texture and your 2k bumpmap,but the results are the craters being "eroded" and losing your shape,specially when you get very near the moon.How all this works?
Anyway,I know that johnvanvliet had done a 16k normal map for the Moon,but I can??t find it.Where is it?

[t00fri]

Daniel.....

I wondering if is it worth to use smaller bump/normal
map than the base texture.For example,the biggest normal map for
the Moon is 4k,so if I use it with a 8k or 16k texture,it seem a little
strange.I have to choose between bigger resolution and sense of
depth.But why no one ever did a 8k or 16k bump/normal map of the
Moon?

That's obvious: for a good normal map one needs VERY smooth
elevation data and those are LACKING in higher resolutions for the
Moon. And the lower resolution data are also of pretty bad quality.

I did make a 8k normalmap of the moon, using some of my tricks.
However, since it is not a bonna-fide normalmap based entirely on
elevation data, I will certainly not publish it.

Just to make sure: Of course one cannot simply blow up a 4k
normalmap with GIMP or Photoshop to get an 8k one I strongly
hope that you knew this...

I was experimenting this with Iapetus.I put t00fri??s 4k texture and
your 2k bumpmap,but the results are the craters being "eroded" and
losing your shape,specially when you get very near the moon.How all
this works?

Anyway,I know that johnvanvliet had done a 16k normal map for the
Moon,but I can??t find it.Where is it?

In general, normalmaps are even more important for the visual
impression than an (unshaded) base texture! So in ALL cases I
recommend to rather take a smaller sized base texture and make the
normalmap resolution as big as possible. You can try out for yourself:
just replace the BMNG base Earth texture by a purely white one, i.e.
without any details visible. You will still get a pretty good view of the
Earth's surface JUST from using a good normalmap.

Here is such an example with ONLY my 64k normalmap, NO base
texture. It's a view of the Andes as you will recognize.


Bye Fridger

[danielj]

In general, normalmaps are even more important for the visual
impression than an (unshaded) base texture! So in ALL cases I
recommend to rather take a smaller sized base texture and make the
normalmap resolution as big as possible. You can try out for yourself:
just replace the BMNG base Earth texture by a purely white one, i.e.
without any details visible. You will still get a pretty good view of the
Earth's surface JUST from using a good normalmap.

Here is such an example with ONLY my 64k normalmap, NO base
texture. It's a view of the Andes as you will recognize.

Ok,but how can I replace a base texture for a white one?I have Photshop CS and don??t have a clue.Is it to change to black and white?
Anyway,I will first try to do a normalmap based in a single texture,because BMNG is in tiles and few programs are able to "read' this...

[Andy74]

Ok,but how can I replace a base texture for a white one?I have Photshop CS and don??t have a clue.Is it to change to black and white?

In solarsys.ssc, when I put a # in front of the line where the earth texture file is defined, the earth turns blank white in Celestia:

Code: Select all

# Texture "earth.*"

All lines with a # at the beginning are ignored by Celestia.

[t00fri]

precisesly...

[danielj]

But if this is so simple,why so one would bother to create a normalmap or bumpmap?
You can only have to be a texture or 1 copy and do something like this:
Texture "iapetus.*"
#Texture "iapetus.*"

And it IS DONE.You have a new NORMALMAP...

So,soon we can get rid of:
NormalMap "iapetusnormal.*"

or

BumpMap "iapetusbump.*"
BumpHeight X

precisesly...

[selden]

Daniel,

I think you are misunderstanding.

With only a texture map, without a normalmap or bumpmap, you can't see the moving shadows cast by the sun.

They are saying that you can display a normalmap's shadow effects by eliminating the texture map. Without a texture map, Celestia draws a blank sphere where the normalmap's shadows on the sides of mountains and craters are easily seen.

Texture maps add fixed colors to the surface. Normalmaps add moving shadows to the surface, cast by the sun.
Specularmaps add moving highlights to the surface, cast by the sun.
Emissivemaps add fixed lights to the surface.
Opacitymaps add fixed transparent areas to the surface.

[edit]
Using a real texture map as if it were a normalmap will *not* give the correct results, although it may look similar. A texture map is supposed to describe only the coloration of a surface, not the height of its terrain.

Some texture maps are made directly from photographs that have not had the fixed, non-moving, shadows removed from them (e.g. photographs of the Moon). Normalmaps and bumpmaps made from them can only be used for very crude heightmaps. Craters will be high on their east/west sides and low on their north/south sides. Dark plains will be low while bright spots (like the area around Tycho) will be high.

The shadows created by these crude heightmaps and normalmaps will be wrong.
[/edit]