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Material indices/2 Bump Maps on one object
by Matvei Mihaljov

In this tutorial you'll learn to give an object two different materials, and to create bump mapping effects. I assume you have the basic modeling skills (creating objects, scaling, translating) and are familiar with the Blender interface. This is my first tutorial and any comments (including ones considering my English) are most welcome at matveim@hotmail.com

We'll start off by creating a Cube in the middle of the scene. Still in editmode, scale it 3 times.

With all vertices selected, subdivide it one time.

Create a new material.

Open up the EditButtons screen. You'll see a group of buttons that control the Material indices.

MATERIAL INDICES
Each face of a mesh has a material index number. Every face will use the material set for that index number. Therefore if the object has only one index, every face will use the same material.

The topmost button (1 Mat:1) tells us that there is only one index created for this object (first number), and that the first index is the active index (second number).

Now we will add a second material index. Push the button labeled "New". The label on the topmost button should be now "2 Mat:2". Clicking on the left edge of the button will browse backwards through the indices, and vice versa. As you will notice the label on the top doesn't change, because the both of the indices use the same material. Activate the second index and open up the MaterialButtons.

You will notice that the first material now has two users. That is due the fact that both of the indices are considered users.

Add a new material. Now both of the materials have only one owner: "Material" is owned by first index, "Material.001" by the second index.

Although we created the second material index and assigned a new material to it, all of the faces in the mesh are assigned to the first index. Open up EditButtons and turn on the EditMode. In the TopView select the center and the bottom right vertices. Push the ?-button to see which index the faces are assigned to. The top label will change to "Material". Push the right edge of the "2 Mat:1" button to select again the second index. Push assign.

To see more clearly what we have achieved open up the MaterialButtons and change the color of Material.001. Push the "z" button on your keyboard and rotate the view to watch the results.

Now we'll make the "Material" the same color as "Material.001". Open up the EditButtons and select the first index. Go back to the MaterialButtons, and turn the color to blue also. Now the cube is evenly coloured.

Next we will add two different bump maps on this one object! You should have the first index selected now. Open up the TextureButtons.

The texture "Tex" has now 2 owners: "Material" and "Material.001". Push the button labeled "2" to make a copy of "Tex" for both of the textures and thus make it a single user texture.

Now don't get confused: "Material" is the owner of "Tex.001" while "Material.001" is the owner of "Tex".

Now let's make the "Tex.001" a marble texture.

Open up the MaterialButtons. Turn the Col mapping (texture affects the color of the material) off and the Nor mapping (texture affects the normals of the material) on, and adjust the Nor value to 5. (how much the texture affects the material's normals)

Open up the EditButtons and select the second material index. Go back to the TextureButtons and make "Tex" a stucci texture.

Open up the MaterialButtons, turn off the color mapping, turn on the normal mapping and adjust the Nor value to 5.

Hang up a lamp and render!