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View Full Version : Normal map plug-in renders are leaden, dark



undule
11-10-2004, 04:18 PM
I am wondering if anyone else has experienced rendering problems with the current normal map plug-ins found here: http://amber.rc.arizona.edu/lw/normalmaps.html

It seems most people have no issues, juding by the picture posts I have witnessed both here and over at Zbrush Central. However, when I try to render a lowpoly mesh with a normal map (either tangent or adaptive) I get a very dark, unusable image. I have followed the instructional manual precisesly, but the result is simply in error: the edges take some light, but the mesh center is completely black, or at best, dull gray. It's like the shader is eating the light.

I've scoured various forums and the internet at large for a solution to this problem, but I've only managed to discover a smattering of posts from frustrated individuals suffering as I am -- but no suggestions or solutions to be found.

So, anyone at least share this issue, brothers-in-aggravation? Any possible solutions? Alternate plug-ins, perhaps?

Any help would be greatly appreciated. :)

jasonwestmas
11-10-2004, 04:35 PM
I've used these plugins a little.
I just use the default settings when generating the map. Everything seems to work pretty good when I render. Could you show me what the map looks like? If you want specific default settings I can check for you.

I've got to say, if you have Zbrush2 you should try generating your map from there. I've gotten slightly better results and the map renders a 100x faster.

undule
11-10-2004, 04:48 PM
I will post some pictures when I get home tonight, as I'm posting from work. I would like tol add, however, a bit on my process. I'm extracting the normal maps from Zbrush and using Z's UV mapping which is perfectly seamless. I'm flipping the normal map on the V, and have tried using both tangent and adaptive. World maps seem to render slightly better than tangent, but the results are in error nonetheless; all of them being incredibly dark and gray, leaden.

What's disconcerting about the problem is this, from the developer of the plug-in:


Fixed a bug in which the normal map's texture layer was not being evaluated correctly for some people. This bug would result in the model being rendered as a solid gray object. I never encountered this problem on my system, but was finally able to reproduce it on someone else's system. This made it very difficult to track down this bug, and hopefully I have found the solution

Though I'm not getting a completely solid gray object, the phenomena is obviously related -- and unsolved. So, I'm guessing it could be something specific to my driver/hardware configuration rather than an error on my part in setting up the scene, applying the shader, etc.

I'm on an Athlon 2.2 with a Radeon 9600 --and I know Radeon's have conflicted with Lightwave in the past, perhaps this is my problem? Lawdy, it's frustrating.

Thanks for the reply, though. :)

IZZE
11-11-2004, 05:03 PM
I started on this as well a while back and never found the time recently to get back to it.

Try putting your lightsource behind the model and then render from the front. Does it look a bit better, but still a little off?

If so, when creating the Normal Map in Z, under prefrences> there is a option to filp X, Y etc. this will invert the greens and reds to help the normal shader in lightwave. There is also the option to flip V (or Horz, not sure) so you dont have to do it in PS.

You will have to recreate the map after turning on these options, then export the texture.

I have not tested this, but it is what I was going to try next. Im not sure which value X is etc.

Report back

jasonwestmas
11-11-2004, 06:27 PM
Yeah, very likely you have to invert your warm and cool colors in the normal map or else move your light source behind the model. You'll find that warm colors will be in more or less of a shadow and the cool colors will be lighter.