Adding Dirt and Grime to 3D Game Animation

Although most game-animation textures are created externally and wrapped onto objects, most 3D software programs also include a separate set of tools for painting directly on the objects themselves. Using these painting tools, you can add details, such as dirt and grime, to the texture applied to the object after the texture image has already been applied.

One helpful way to use these paint tools is to add realistic dirt and grime to objects. Adding these layers of dirt to the texture map can be tricky because you're not always sure where the map will match the folds of the skin or the edges and corners of an object where dirt is likely to accumulate. Painting tools are also helpful for defacing nice textures with spray paint to resemble graffiti.

3D painting tools typically let you select from a selection of brushes that offer different styles. You can also adjust the brushes' size, pressure, and color. In some software, the painting tools work only if the surface has a texture file applied to it.

Follow these steps to use the painting tools:

1. Choose the Create --> Polygon Primitives --> Cube menu command.

A polygon cube is placed in the center of the view.

2. Select the Lighting/Shading --> Assign New Material --> Lambert menu command to create a new material for the cube object.

The Lambert2 node in the Attribute Editor is opened with the material properties for the assigned material displayed.

3. Press the 6 key to enable a Texture view.

In Texture view, you'll be able to see the brush strokes as you paint.

4. Select the Texturing --> 3D Paint Tool menu command to access the painting tool, and then select the Window --> Settings/Preferences --> Tool Settings menu command to open the Tool Settings panel to the right of the view pane.

All the settings for the 3D Paint Tool are displayed within the Tool Settings panel. Initially, there isn't a surface to paint on, so you'll need to create one.

You can also switch among the Attribute Editor, the Tool Settings, and the Channel Box using the three buttons located at the top right of the interface beneath the Minimize, Maximize, and Close buttons.

5. In the File Textures section of the Tool Settings panel, click the Assign/Edit Textures button.

The Assign/Edit File Textures dialog box appears.

6. Set the SizeX and SizeY values to 256 and click the Assign/Edit Textures button.

This creates a texture that you can paint on top of that is saved with the scene file.

7. Set the Brush Scale value to 1.0 and the color to light blue, and drag over the top of the image in the view pane.

The color is added to the texture image on all the cube faces.

8. Select the File --> Save Scene As menu command and save the file as Painting tool.mb.

The ability to paint directly on an object's surface is very helpful as you add materials to objects.

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