maya and normal maps ala doom3

[empleh]

Sorry for my ignorance, but what are normal maps? or how are they constructed?

ww

[-=TF=-]

Hi

As I understand this, its basically an colour image representing the xyz axis with rgb colours for a better bump effect.
Where a classic bump is only grayscale (height of bump),
a normal map bump texture looks much more realistic, because each pixel knows its true location in 3dspace.
I think its also called dot3bump mapping, but im not shure on this.

Here is a snip from a doom3 talk:

"For those that haven't heard the word on how this all works, here's the breakdown: Artists begin by making a movie quality model of a level, character, or monster for the game. This super high quality model with a ridiculous polygon count is then run through the engine, with all of its bumps and ridges and details, and gets turned into a normal map which can lay over a much lower polygon count model to make it look like it has all of the bumps and ridges that the original high count model had. The special trick is that this normal map still gets real-time shadows. "It's the Carmack magic that allows us to take something that high quality and take it down into the lower poly count and still have the shadows and detail that you would see on the high count model," says Willits. It's an amazing effect that maximizes detail and performance all at the same time."
...http://pc.ign.com/articles/368/368245p1.html

You can also have a look at http://www.highend3d.com/files/?group=mayashaders#1832
to see how this works in maya.
only problem is it is really sloooow to compute at the moment...
nvidia has a lot of techtalk at their developer site about this.

hope this helped
cheers,
lars

[empleh]

That's what I thought. Can I mail you a shader to try?

ww

[Crode]

lol is that how they did it...... very interesting. I was wondering how they got bumpmaps to work at such high framerate. the carmack is very smart

[DesignDawg]

Hey there,

If I understand what you want correctly, you should check out

Fast Normal Mapping Beta (http://www.highend3d.com/files/dl.3d?group=mayashaders&file_loc=fast_normals-v0.1-.mb&file_id=1997)

On Highend3D. It's in the shaders section if that link doesn't work out.

Ricky

[empleh]

That's what I wrote for him, lol. I Had to post it, it's the only thing that I have accomplished so far today. :-)

I am not sure if it does what is needed. It appears to but I have no way of testing.

ww

[DesignDawg]

Hehehe...

Yeah, I noticed, when I went to Highend, it was right there on top of the new stuff, and when I read the readme, I noticed it said it was in response to a question. I thought, "Weird timing. What a coincidence!" :)

So I came right back and posted it.

Ricky

[ambient-whisper]

personally i think the whole poly"whore"count is just dumb in most cases. i looked at the cryotec site and they could lower the polycount of all those objects by atleast 150k easily and still keep the same look.

http://www.crytek.de/images/gallery/polybump/poly_04.jpg

heh. for 250000 polys ...i would have had tiny details like veins, small muscle details, the guys overall face would have been much higher in detail/subtlety. it just looks like they took the low poly and smoothed it 100000 times.

now im not putting down the technology. i think its kickass. but the demos are making it seem like the artists that made those models worked their ass off to get those 250000 polys. :rolleyes:

[empleh]

I was thinking that it might be good for subdivision models where you can have a relatively low vertex count and infinite smoothness. That way you could use the polymesh in the game with the normals of the subd.

If that makes any sense.

ww

[-=TF=-]

Hey!
Verry cool!!

Just came back and ... :beer: :applause: :bounce:
Big thanks to empleh/ww !!
Seems to do the task quite perfect!
Good idea to post it at HE3D to make it public, its a _real_ smart shader :)

thanks,
lars

[womanonfire]

pardon my ignorance but... what is one supposed to do with this normal map once you've got it? do you use it as a guide to paint a texture or something? or do you texture the high resolution model and then somehow combine the texture and the map to stick onto your lo-rez model ? perplexing technology whRRRR....

[MCronin]

I guess I'll try to explain it.

A normal map is a bump map basicly. The difference is a bump map would usually be greyscale with each pixel in the map representing height. A normal map is RGB, not greyscale, and the R, G, and B channels actually represent the X, Y, and Z of a normal vector of a high polygon surface. Each cahnnel runs from -1 to 1 rather than 0 to 256. So, you have to build a high polygon model to get a nice sampling of surface normals for the map, even if you aren't actually going to make the best use of all those extra polyons in your model. The more polygons you have, the more surface normals you have, the smoother your lighting becomes. Once you have generated the normal map based on a high resolution surface, you then apply the normal map as you would a bump map to a low polygon model. Then, in a game engine or real time viewer or whatever, you can use a pixel shader which will shade the model using the normal map, rather than just the normals of the low poly surface. You are effectively shading a low poly model as if it were a high poly model by borrowing normal information from a high polygon mesh.

The great thing about normal maps is that you can use a high polygon object with complex bump and displacement maps, and translate all that lighting info to an ultra low polygon mesh with as little as one triangle.

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.