Understand the key concepts behind a wide range of texture maps with Digital Tutors...
To paraphrase the popular saying, there are two types of texture artists in the world. There's the dedicated texture artists and then there's the modelers who also take on the texturing role. Regardless of which type of texturing artist you are, it's incredibly important to understand the key concepts behind the texture maps that are used to create the wide range of material types that you'll be called on to create.
The process of texturing is so much more than just adding color to a 3D model, and simply put there are few feelings better than taking a bland chunk of monochromatic geometry and watching it come to life as you transform it into a realistic prop constructed of a wide range of materials like plastic, rusty metal and glass. In this article we'll take a look at some important concepts you'll need to keep in mind as you begin creating texture maps for your own models.
Is Your Model Ready?
While it may be tempting to jump into texturing right after modeling something, most 3D models aren't ready to be textured as soon as they're modeled out. If you take the time to prepare your model properly before texturing, it can save you a lot of headaches later on in the texturing process. For example, it's a good idea to check for issues like flipped normals and to make sure there's a viable UV layout.
While UVing may not be the most glamorous task in 3D, it's still very important to the texturing process because it's literally the guide for your 3D software to know how it should apply any of the 2D texture maps you create to your 3D model. You can have UVs that are a single tile, or you can have them spread across multiple tiles if you need to dedicate more pixels to certain areas on your model.
Check your model is ready before texturing
After you've got the UVs laid out, start simple by blocking out some different materials or shaders to get a rough approximation of the different surface qualities. By starting out simple, you can quickly make changes to areas that should be different without getting bogged down in the details of the materials.
For example, create a simple rubber material to apply to all the rubber areas on your model. Do you think a particular piece should be plastic instead? Apply a simple plastic material instead of the rubber material to get a rough look down for your model. Once you've identified all of the materials you'll need for your model, you can start painting the
There's a couple different ways you can do this. One technique you can use is to output a UV guide from your 3D program and bring it into Photoshop to start painting your textures. Photoshop does have some simple 3D capabilities that can help with this, but depending on your model's complexity it may be best to stick to going back to the 3D program to preview your textures. Or, if you'd prefer a more direct method, another common technique is to paint textures directly onto the 3D geometry in a program like ZBrush or Mudbox.
Creating everything from scratch is nice, but sometimes you've got to get things done fast and often times it's just faster to use a photograph as a way to add real-world detail to your textures. If you're taking your own photos for textures, make sure your images are as flat as possible.
Most 3D scenes will have lighting added to them later, so if you have lighting baked into the textures it can break the illusion of reality. For example, if you have a texture with a shadow being cast on the right side of the objects in the texture but your 3D scene has a light on the right side, the viewer's eye will know something isn't quite right because shadows shouldn't be cast on the same side as the light source. For that reason it's a good idea to bring your textures into Photoshop to remove any sort of lighting or shadows in the image if possible.
It's worth pointing out that a lot of games do have baked lighting as a technique for faking the lighting. This is done intentionally, but it's usually done a little later in the pipeline than the creation of the initial textures. Generally speaking you'll want to remove any existing lighting from raw images.
You can learn more about projection painting in Texture Projection Techniques in MARI
Choosing the right texture for you surface
When you think about texture mapping, the first thing that comes to mind is probably the color map. The aptly-named map is basically defining all of the surface color for your materials, without any of the lighting or shading information. Color maps, which are also sometimes referred to as diffuse maps, can go a long way to defining surfaces as being made from different real-world materials.
You can also use color maps as a starting point for many other texture types, like bump or specular, because the color often changes in the same areas as other aspects of the material change. For example, in the image above you'll notice the color changes around the bumpy areas on the character's forehead. Not only are there color differences there, but once you've created the color map that can be a great start to a bump map without having to recreate all of those bumpy areas.
You can learn more about creating color maps in Your First Day in MARI