PDA

View Full Version : normal map questions for a game artist

Scott31
10-26-2009, 11:21 PM
http://i275.photobucket.com/albums/jj314/scottmichael28/test01.jpg
http://i275.photobucket.com/albums/jj314/scottmichael28/test03-1.jpg
After much, much study I have a few questions about normal maps. I aim to be an environment artist and am working on a game art portfolio.

1) What is the role of lighting here? Is it actually changing the normal map at all. Is it really true that you should use an omni light specifically to test it?

2) I've noticed tutorials chamfering edges of squares (like the 1st pic above). Is that usually done or just for lesson sake? I've also been told it's pointless to make a normal map just to bevel the edges.

3) Similarly just how often are normal maps used in game art? In other words is every single game model normal mapped or just when a specific detail is needed (like a gaping spherical hole in a box)?

4) Are bump maps usually used with normal maps or does the normal take it's place? It seems as if I'm being discouraged from just using the color maps detail (dirt, grain, texture, etc.) for the normal. I thought: make the normal in 3ds Max for the major details (gaping holes, etc.) and then use the NVFilter for the little details. I've looked at game art portfolios and found that they post the color, spec and normal maps without really showing any kind of bump map and the normal maps is "clean" of rough textures typically (just raising and lowering details to simulate the appearance of more geometry).

(See 2nd pic above) I combined a filtered layer of some noise with the baked layer (filtered layer on overlay with the blue channel high output reduced to 127). Is this right to make the "bump" in the normal map or should it be a separate grayscale texture in the actual "additional bump" slot in 3ds Max's normal bump material?

5) What are the tri-strips?

6) A little off subject, but are color, normal, and spec maps the necessary 3 to know for game art? That certainly seems to be the case from my studies (forum searching). I'm aware that some 3d art involves a whole plethora of maps including separate color and diffuse, spec, glossiness, illumination, normal, bump, AO, of course opacity maps (OK, I know about opacity too which is handled by a certain color in the game engine), reflection, refraction, and displacement maps. Ok...exhale. That's a lot of maps...intimidating.

Thanks!
Piflik
10-27-2009, 05:46 AM
You chamfer hard edges to be able to put all faces into one smoothing group. Having hard edges in th model means, that you'd have to split thoe edges in the UV Layout. Also, most engines split the model into different parts based on their smoothing groups, thus creating the same vertex count as chamfering. Also the chamfered edges give you a much nicer profile, easier for the normal map to create nice rounded corners.

Normal maps are just used as needed. normal mapping a small box, that will only be seen from afar is a waste of texture memory.

Bump is not really used. All you can do with Bump, you can do better with normal.

Color, Spec and Normal. More only in certain cases.
LosPescados
10-27-2009, 08:11 AM
Does an additional map ? F.e a normal map/specular/self-ilumination map. Take additional texture space when you have a diffuse map ?

-Tom
Piflik
10-27-2009, 04:55 PM
Of course. Every image has to be loaded into your memory.
Scott31
10-27-2009, 05:57 PM
You chamfer hard edges to be able to put all faces into one smoothing group. Having hard edges in th model means, that you'd have to split thoe edges in the UV Layout. Also, most engines split the model into different parts based on their smoothing groups, thus creating the same vertex count as chamfering. Also the chamfered edges give you a much nicer profile, easier for the normal map to create nice rounded corners.

Normal maps are just used as needed. normal mapping a small box, that will only be seen from afar is a waste of texture memory.

Bump is not really used. All you can do with Bump, you can do better with normal.

Color, Spec and Normal. More only in certain cases.

Thanks alot for that info. It makes sense to me as well. I'm working on a scene right now that has alot of boxes that are only seen from a distance. I couldn't help but wonder if it was necessary to make normal maps for all of them. It never occured to me for some reason to balance the need from the normal map against the extra memory. Probably because I've never actually worked on a game before.

Also that chamfered edges issue makes alot of sense.

thanks
OneThousand
10-28-2009, 08:59 AM
in my opinion, if you have the time, you should generate a normal map for those boxes for texturing purpose. Open your base diffuse map with photoshop, then put the normal map above the diffuse map layer with the multiply blending mode. I find it great as it helps to enhance my texture
CGTalk Moderation
10-28-2009, 08:59 AM
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.