f13.net forums - Texture Mapping Materials

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April 19, 2024, 09:31:24 AM

we're back, baby

I currently work on a little iPhone development project.

One part of the project involves 3d dice varying from D4 to D20 (basically all platonic solids and the D10).

I want to offer different color schemes for the dice (Think of it as roleplaying dice sets with different materials, paintjobs)

The OpenGL coding part is not the problem. Me not being a designer is. All of the books I know talk about the technicalities of texture mapping and lighting (which functions to call, which OpenGL properties to set in which way etc.) as I said that's not the problem.

None of those are talking about what I need to do to make the result actually look good however.

Do any of you know any good resources on the design side of 3d graphics? (lighting, how to design textures etc.) for laymans? I don't want to become an absolute design expert but I want my project at least not to look like comnplete crap.

What's the problem you are having? Are you having trouble figuring out where to draw stuff on the texture so things are "oriented" in the proper way? Are you having trouble figuring out the "shape" of the texture and how it "folds" back together?

Not really.

I have the problem of creating/obtaining textures or creating/obtaining the right materials for the objects.

All of the tutorials and books I found only explain what you need to do to work with materials in OpenGL. How to set the lighting how to set color what's the difference between specular ambient and other lighting elements. How to apply textures to objects and so on.

I am currently more interested in the design side of things. How do I create/obtain good looking textures? What steps do I need to do if I want to recreate the look of certain materials (Metal, Glass Plastic etc.) Correct lighting basics etc.

I don't want to systematically try all of the knobs for the next half year until I find something that looks good.

RPG Dice sets usually emulate the look of certain materials (Metals, translucent materials, gems, ceramic or china) and I want to be able to use some of those materials in my app without paying 200 dollars for a ready made set of 3d models from some model exchange site.

I also want to learn how it's done

Quote from: Jeff Kelly on July 21, 2009, 05:59:36 AM

Ah okay. Recreating the look of "smooth" materials is mostly a function of how light is reflected off of the objects. Things like the size of the highlight(s), the color of the highlight, the amount of light reflected back, etc. is what gives the illusion to textures looking like metal or plastic or whatever. The way I learned about this back in ancient times when I actually knew about this stuff was to browse material libraries in Mac 3D applications and studied the lighting settings for the major types.

I'm not sure what would be the easiest and cheapest way to do this now. Maybe there are some Open Source rendering packages that have material libraries you can browse in the same way?

Edit: what

Quote from: Trippy on July 21, 2009, 06:20:23 AM

The way I learned about this back in ancient times when I actually knew about this stuff was to browse material libraries in Mac 3D applications and studied the lighting settings for the major types.

I never even thought about that. That would be a good start I suppose.

Quote

I'm not sure what would be the easiest and cheapest way to do this now. Maybe there are some Open Source rendering packages that have material libraries you can browse in the same way?

The only one I know of is Blender. I have a look at that one.

POV-Ray is an Open Source raytracing program. You may be able to find some stuff in there as well.

http://www.povray.org/

You could always pay me. Oh ho ho ho. Reallllly?

It sounds like you need someone to design your dice, and textures. if you don't want to pay me sad

, then I suggest you take a look at some of the stock texture packages for things like Marabel, and swirly stones, or, go down to your hobby shop and start taking pictures.

Not knowing your design, if you are just tossing die, then your lighting would be constant anyway.

There is a ton of that stuff out there, especially for use by those Gem games.

The approach Mrbloodworth is advocating (not the paying him part of it awesome, for real

), which is either just to use stock textures for bitmap graphics programs or to learn how people "fake" it in programs like Photoshop, is easier than what I wrote above. It's probably a bit much to expect your iPhone app to be doing real-time lighting and reflections while rolling dice though that might kind of a fun exercise on it's own.

As an example you can simulate metal without trying to simulate lighting the object by giving it a "brushed metal" look a la the Mac OS X app look in some apps and there are lots and lots of Photoshop tutorials on how to do that. The same is true with how to make the "glass" (aka "gel") buttons from Aqua. Making an actual glass die, though, isn't that simple.

http://wiki.blender.org/index.php/Doc:Manual/Materials/Properties/Specular_Shaders

The most useful part of that page is some basics on how the diffuse and specular reflection attributes for material come together in creating various appearances. For more detailed and in-depth examples there's plenty tutorials on texturing for various 3d applications (Maya, Lightwave, 3ds Max) and all these programs utilize the same basic concepts, that should be of some help when tweaking your own stuff.

You might be able to get something out of RenderMonkey if you want to fiddle with shaders (http://developer.amd.com/gpu/rendermonkey/Pages/default.aspx). Has a while since I've messed with it so am not sure what level the barrier of entry is with the recent versions.