For a game project I want to create a tileable volumetric texture, say 
64x64x64 in size, and apply it to some rocks/stones of variable shapes 
and sizes, that are in the game.

So first of all I want to find an editor where I can create the texture 
and preview it. I did some googling on the topic, but didn't come up 
with anything. Could I use 3d Max, and how do I save a volumetric 
texture from Max?

Also, I need to pick a 3d bitmap file format to use. What alternatives 
do I have, and which one is best?

cheers,
Morten Perriard

Morten Perriard wrote:

> For a game project I want to create a tileable volumetric texture, say
> 64x64x64 in size, and apply it to some rocks/stones of variable shapes
> and sizes, that are in the game.
> 
> So first of all I want to find an editor where I can create the texture
> and preview it. I did some googling on the topic, but didn't come up
> with anything. Could I use 3d Max, and how do I save a volumetric
> texture from Max?

I wouldn't use 3D textures for this. They are often too slow or not well
supported and they take up a lot of memory. For a game, just use some nice
tilable 2D stone texture. You can easily produce one by photographing some
stones, cutting out part of the photo and sending it through the Gimp
resynthesizer. Then use a 3D tool of yout choice to model the geometry of
the rocks and do the UV mapping (e.g. I would use blender for this, but 3d
max can do this too, I guess).

        http://www.gimp.org/
        http://www.logarithmic.net/pfh/resynthesizer
        http://www.blender.org/

> Also, I need to pick a 3d bitmap file format to use. What alternatives
> do I have, and which one is best?

I would stick with PNG -- it compresses very well (lossless) and supports
alpha channels. Read/write access is available through the libpng project:

        http://www.libpng.org/pub/png/libpng.html

Arne

-- 
[--- PGP key FD05BED7 --- http://www.root42.de/ ---]

Thanks, Resynthesizer looks really cool! I'll look into that.

I'm a little hooked on the idea of the 3d textures however, despite the 
disadvantages you mention.

Perhaps I should explain my situation better. I'm writing a game that 
takes place in outer space, in a dense asteroid belt. So, I'm computing 
houndreds of different asteroids varying greatly in shape and size. I 
only want to use one texture for all asteroids, and 64x64x64 in RGB, 
with MIP levels is an acceptable memory usage to me (less than 2 mb).

The asteroids can be viewed by the player from all angles, and at far 
distance as well as close up. Using solid mapping I can avoid problems 
with warped / distorted textures. Also, I suspect computing UV mapping 
would be more complicated than a simple transform of object coordinates 
to UVW mapping coordinates.

Googling a bit more, I found this:
http://josua.hoengermedia.ch/aboutme_programming_vloop.htm
(I wrote him an email but it bounced, so that was a dead end..)

cheers,
Morten Perriard


Arne Schmitz wrote:
> Morten Perriard wrote:
> 
> 
>>For a game project I want to create a tileable volumetric texture, say
>>64x64x64 in size, and apply it to some rocks/stones of variable shapes
>>and sizes, that are in the game.
>>
>>So first of all I want to find an editor where I can create the texture
>>and preview it. I did some googling on the topic, but didn't come up
>>with anything. Could I use 3d Max, and how do I save a volumetric
>>texture from Max?
> 
> 
> I wouldn't use 3D textures for this. They are often too slow or not well
> supported and they take up a lot of memory. For a game, just use some nice
> tilable 2D stone texture. You can easily produce one by photographing some
> stones, cutting out part of the photo and sending it through the Gimp
> resynthesizer. Then use a 3D tool of yout choice to model the geometry of
> the rocks and do the UV mapping (e.g. I would use blender for this, but 3d
> max can do this too, I guess).
> 
>         http://www.gimp.org/
>         http://www.logarithmic.net/pfh/resynthesizer
>         http://www.blender.org/
> 
> 
>>Also, I need to pick a 3d bitmap file format to use. What alternatives
>>do I have, and which one is best?
> 
> 
> I would stick with PNG -- it compresses very well (lossless) and supports
> alpha channels. Read/write access is available through the libpng project:
> 
>         http://www.libpng.org/pub/png/libpng.html
> 
> Arne
> 

Morten Perriard wrote:
> 
> For a game project I want to create a tileable volumetric texture, say 
> 64x64x64 in size, and apply it to some rocks/stones of variable shapes 
> and sizes, that are in the game.

Are you interested in the interior of the rocks? That is, are you cutting
into them or using pseudo-radar to search for mascons inside them? Are they
partly transparent?

If none of the above applies, you are probably better off with a 2D texture or
set of 2D textures to map onto the outside surface of the rocks.

> So first of all I want to find an editor where I can create the texture 
> and preview it. I did some googling on the topic, but didn't come up 
> with anything. Could I use 3d Max, and how do I save a volumetric 
> texture from Max?

I deal with volumes all the time, but I don't try to draw them by hand.
It would be a bit tedious for a 512x512x2000 volume :-)

> Also, I need to pick a 3d bitmap file format to use. What alternatives 
> do I have, and which one is best?

Try TIFF -- it has a 3D mode.
Or MNG, the 3D variant of PNG. (OK, so most people use the 3rd dimension for time,
but you certainly don't have to.)

--
Andy V