3D Paint Tool
This tutorial covers how to use the 3d paint tool to paint texture directly onto your model in Maya.
Select the model that you want to paint. Your model needs to be UV mapped. If it's not already UV mapped, use automatic mapping. To use automatic mapping, go to the polygons menu set, select your model, and go to create UVs>automatic mapping.
Set the menu set to rendering.
Step one - Select your model and go to texturing>3d paint tool. Open the tool settings by going to display>UI elements>tool settings.
Step two - There'll be an X over the brush. This tells us that there has not been a texture assigned to the shader that's assigned to the model. Make sure the attribute to paint on is set to color. You don't have to; you could paint a bump map, a transparency map, etc. Roll down the tool settings and go to assign/edit textures.
Step three - Here's a rundown of the attributes.
Brush U - This is the brush's radius.A quick way of changing this attribute is to press B and drag with your mouse horizontally.
Step two - Click on the select brush icon to open the browser and select a brush.
Color - This is the color that's being painted. You can use the eye dropper to grab color values from the interface, or click on the swatch to open the color chooser.
Besides using the artisan and paint effects, you can also erase, smear, blur, and clone.
Saving the textures
You can save a texture by clicking the save button below the assign/edit textures button.
In case you forget to save, it's best to have the option "save texture on stroke". That way it will save after your last brush stroke. The file will be saved in My Documents/Maya/Projects/your current projects(default)/3dPaintTextures/name of file/.
Painting on both sides at once
You can paint with a mirror of the brush on the opposite side so you can paint on both sides at once. Roll down to stroke and check reflection, then select the axis you want to mirror across.
This tutorial has covered the basics of using the 3d paint tool.