[DaBrain]

I just read an article about normal mapping. One statement was quite shocking for me. Surface parts should not share the same part of the UV map. Mirroring is forbidden...

Now that would ultimatly destroy all my plans to create normal maps for FS2, SoL and maybe other projects.

I also read this restiction depends on the engine.

So, do I have a problem now?

I does make sense...

[Bobboau]

this sort of thing depends largely on the implementation.

[Nuke]

i was reading about this too. it is still possible to generate normal maps for mirrored models. it just takes some tweaking to get it seamless. i have of ships that have seams in obvious places, mainly along the centerline. the pf satyr has a nice ugly line that goes right over the cockpit window at a funky angle, it should look pretty whack normal mapped.

if youre using a hi poly mesh to generate your uvs, you just neer to remove all the copyed/mirrored parts of the model so that you dont have any duplicates in the uv map. (god damn this is gonna make the ragnarok class a ***** to normal map). programs like melody are pretty smart about this, and may be able to generate the normal map anyway.

if you still get seams, tweak your uv normals before generating your normal map. i think max lets you do this, im not sure though. i doubt any low-end modeling program gives you this control.

directly edit the normal map. this is easyer if you keep your seams either perfectly vertical or perfectly horizontal in the uv map (i do this anyway as it would be a pita to uv two sections at an angle). just draw a green or red line (depending on which way youre going) with low opacity. re-normalize and save and check it in your modeling program. repeat untill it looks right.

[DaBrain]

I know some engines will cause trouble with mirrored parts.. I hope FSO won't be one of them...
(It's a waste of time to work on normal maps now, if they have to be redone later.)


BTW, I have tested the MAX render-to-texture thingy to export a normal map. Surprisingly the result was just... blue....

We don't need an UV map for the high poly model, right? How can I get the normal map to match the UV map of the low poly model then?
There doesn't seem to be a single good tutorial for this in german.

[Flipside]

By rights, as long as the UV Map is read correctly, this shouldn't be a problem, the Ogre isn't so much the UV Mapping as the lighting itself. You know when you Mirror a UV Map, letters go the wrong way round on the opposite side? So does lighting when you mirror the map, So everything on mirrored side will react to light the opposite of how it should. It shouldn't be noticeable most of the time, but it is worth bearing in mind

[DaBrain]

Yeah, I hope that's won't be too bad. It's not very easy to imagine it visual.

It would proabably look like a kaleidoscope effect, when the mirrored parts are neighbours. Good to know that this exact style of UV mapping was used for most fighters in FS2... duh...

[Bobboau]

that's one of those 'based on how it's implemented' things, there are ways to get around the inherent problem, for one thing I don't know how taylor is implementing his bumpmaps system but if you calculate tangent and bitangent vectors in addition to normal, this will un-mirror the texture in the appropriate situations, unfortunately tangent/bitangent calculation can be a bit of a pain in the ass.

[Nuke]

I know some engines will cause trouble with mirrored parts.. I hope FSO won't be one of them...
(It's a waste of time to work on normal maps now, if they have to be redone later.)


BTW, I have tested the MAX render-to-texture thingy to export a normal map. Surprisingly the result was just... blue....

We don't need an UV map for the high poly model, right? How can I get the normal map to match the UV map of the low poly model then?
There doesn't seem to be a single good tutorial for this in german.

you mean that part in the advanced tutorial that tells you how to generate normalmaps for tiles in max? i got a max 8 scene set up to convert a bump map into a normal map, as per the instructions in the tutorial plus some extra tweaking to improve render quality. i find the result is much better than what the nvidia plugin can generate (which no doubt uses the same technique with an objoiusly less advanced renderer).

basicly i set up the lights as discribed, i then locked the camera directly onto a 20x20 hi poly plane. i applied a displace modifyer which you can load a heightmap into, tweak the displace value to the desired height and hit render. it workes pretty well.

this is where perserving all my layers layers in photoshop textures is gonna pay off. i can black out the layers and apply an inner glow in the blending options setting it to the right values can generate a bump map of the texture, without having to redraw anything.

anyway let me know if you want my .max file.

[Taristin]

this is where perserving all my layers layers in photoshop textures is gonna pay off. i can black out the layers and apply an inner glow in the blending options setting it to the right values can generate a bump map of the texture, without having to redraw anything.

Hmm... *tries this*

*likes what it does*

*makes bump maps for his lizard ships*

[Nuke]

btw that applies to any kind of map file, i use the same psd file as the base for diffuse,env,glow,shine, and now normal maps. learning to use layers in photoshop is probibly the most important photoshop skill you can have to do texturing. it makes remixing a texture snap, just tweak each layer systematically. it may take me longer to do the main texture, but the quality is much better, and i can make any other map for that texture in less than 15 minutes.

[Taristin]

btw that applies to any kind of map file, i use the same psd file as the base for diffuse,env,glow,shine, and now normal maps. learning to use layers in photoshop is probibly the most important photoshop skill you can have to do texturing. it makes remixing a texture snap, just tweak each layer systematically. it may take me longer to do the main texture, but the quality is much better, and i can make any other map for that texture in less than 15 minutes.

Yea, thats what I do, also. I just never thought to use the outter glow effect for bump maps until you said it, and it seems so obvious now.

[DaBrain]

@Nuke You cheater! You're supposed to spend hours on a high-poly version of the model. 

[bkd86]

Well the normal mapping would work the best when you have a UV mapped model. Also the textures look the best using this method. If your worrying about using the existing files (tiles) you can always cut and past them to fit your UV/texture map. Just creat a grayscale image and you can use that for normal map generation and specular mapping. There is a really cool program called crazybump. It is a beta program that converts photos/textures to normal maps and height maps. Its free and easy to use. Plus you can tweak them in real time while viewing them.
http://boards.polycount.net/showflat.php?C...=0&fpart=1&vc=1

Or if your a really ambitious modeler and love the really high poly modeling, you can make a high poly model (20+k polys) and project that detail on a lower poly (SCP highpoly) model. A program called xNormal has been recommended by of the guys in the mod team I'm on (for HL2). http://boards.polycount.net/showflat.php?C...0&fpart=12&vc=1.

[Nuke]

@Nuke You cheater! You're supposed to spend hours on a high-poly version of the model. 

well tiles when you think about them are planner and its incredibly easy to make normal maps for, as its just a vertical porjection. if you look at nukemod i seldom use tiles, the ssj dante and the sg pyre (which im debating the removal of, as sentry guns dont add too much to the game unless you ad of them, and the things just an htl nightmare for that). im actually working on the high poly vultre which im definately gonna normal map. so wel see how much work it really is.

[DaBrain]

Nuke? Is this what you meant for tile maps?

[Flipside]

Yup, I even use a program which can convert heightmaps into anything up to a roughly 2-million polygon plane

[Nuke]

yea thats what i do, a really good way to do it.

[Scooby_Doo]

Ok how did you do that? Which program did you use?

[Flipside]

I use a program called Vue D'Esprit 5 for it, though I think Bryce offers exactly the same feature. Basically, you use your heightmap to create a landscape and then export the landscape as a .obj file

[DaBrain]

@Scooby_Doo

MAX can do exactly the same... just as sidenote.