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kovacsp

Volumetric wood texture

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kovacsp    306
Hi all, now I'm looking for a volumetric wood texture for days, but cannot find any to download or even to purchase. Procedural woods i've seen so far do not look so good and far from realistic. Also, I would rather not go to the forest, cut down and slice a tree and scan the slices :) Nobody ever created a real volumetric wood texture somehow? Any ideas? kp

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DogCity    553
I don't think volumetric is actualy a term you could apply to a wood texture. Volumetric is usualy used to describe a 3D atmospheric affect, like Plumes of smoke. But, maybe i'm barking up the wrong tree.

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Sneftel    1788
Actually, volumetric textures are perfect for wood. "Volumetric" simply means that it is defined over a volume, not over an area.

However, in practice they usually aren't used, just because scanning and cleaning a volumetric texture is such a huge job and the resultant texture is so huge. Instead, people tend to use either 2D textures, or procedural volumetric textures (usually based on Perlin noise).

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kovacsp    306
Sorry guys, my post was originally targeted for the DirectX forum, and the term volumetric means 3D texture for us there :)
A 128x128x128 volumetric texture looks like 128 slices of wood at 128x128 resolution. Actually, they can be used as textures on today's video cards, all you have to do is to use 3 texture coords instead of two.

I'm looking for a volumetric texture for wood so that when I cut a textured wooden object, I wouldn't have to fake the internals of the wood pattern there, in real time. It would be just there by definition :)

One example (sorry, I couldn't find better):


kp

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DogCity    553
I've learned something today :). Out of intrest, is this technique used much, or do you forsee it being used more as hardware restraints ease? I can't help thinking it would cause a fairly serious strain on most systems. Hmm, did Red Factions Geomod engine use volumetric textures?

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kovacsp    306
Quote:
Original post by DogCity
I've learned something today :). Out of intrest, is this technique used much, or do you forsee it being used more as hardware restraints ease? I can't help thinking it would cause a fairly serious strain on most systems.


You're right, volumetric textures need serious amounts of video memory on board to load. But cards have more and more, and as I can see, the makers new rendering techniques are not ofraid from using these if needed.

For example, almost all procedural texture shaders (like wood, marble) use a volumetric noise textures, because it is still cheaper then generating noise in the pixel shader. Then, I've read about a per-pixel displacement mapping algorithm today, which stores some precomputed stuff in a volumetric texture.

My idea was: if it worths to use a volumetric texture for noise, then it would be better to use a real wood texture directly.

Quote:
Hmm, did Red Factions Geomod engine use volumetric textures?

I don't know that, sorry..

kp

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Jarrod1937    522
That is very interesting. Well knowing what i know now i would just ahve to say its too much of a pain to make them so goodluck finding them. However procedural textures i believe is the best way to go for this case. What is the procedure to make volumetric textures?

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kovacsp    306
Quote:
Original post by Jarrod1937
That is very interesting. Well knowing what i know now i would just ahve to say its too much of a pain to make them so goodluck finding them.

This is what I was afraid of...

Quote:
However procedural textures i believe is the best way to go for this case.

I already tried some, but they were all very far from realistic..

Quote:
What is the procedure to make volumetric textures?

These algorithms usually create concentric rings along some axis, one lighter and one darker brown, etc.., but perturb the circles by some noise. Some random noise may be added then, but usually this is the main idea.

You can see some samples in Ati's RenderMonkey. (they are shader driven)

kp

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RJD_Geosphere    122
Very cool technology. How do you make these textures needed to make this volumetric wood? Is it at all possible to just take a pic of the 3 textures needed to make it? Personally if it's for a game i'd just replace the meshes after they get chopped.

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Radan    404
No actually you would need to take as many pictures as is the resolution of your Volumetric Texture, So if its a 128^3 texure you'd need to take 128 pictures.

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