UV mapping tips

Maya provides a number of features that let you easily create and edit UV texture coordinates for texture mapping your polygon and subdivision surfaces. The UV Texture Editor (Edit UVs > UV Texture Editor) is the primary tool for arranging and laying out UVs for optimal textures.

Knowing how to arrange UV texture coordinates is an important skill to master that depends on whether you are generating a new texture using the UVs as a guide, or if you are adapting the UVs to optimally fit an existing image. The best arrangement depends on the types of textures you will apply and also upon whether you are creating rendered images or models for interactive games. A full description of UV arrangement is out of the scope of this guide but you should consider the following guidelines:

Keep UVs within the 0 to +1 texture coordinates

The UV Texture Editor displays a grid marking the texture space for UVs. The working area of the grid begins at 0 and extends to 1. By default, the UV mapping operations in Maya automatically fit UVs within the 0 to 1 coordinates. While it is possible to move or scale the UVs so they reside outside of this 0 to 1 region, you should keep the UVs for a surface positioned within these 0 to 1 coordinates, in the majority of situations.

When the UVs extend beyond the 0 to 1 range, the texture will appear to repeat or wrap around the corresponding vertices when viewed in the 3D scene or rendered image. The exception to this guideline is when you actually want the texture to repeat on the surface, such as a brick texture along the model of a wall.

Avoid overlapping UV shells

UV points have interconnecting lines that form a shape, called a UV shell. If any of the UV shells overlap in the UV Texture Editor, the texture will appear to repeat on the corresponding vertices. In general, you should avoid overlapping UVs, unless you want the texture to repeat. For example, if you want the arms of a character to share the same texture pattern, you can place the UV shell corresponding to one arm on top of the piece corresponding to the other arm, using the Move UV Shell Tool.

Some UV projection operations often result in overlapping UV shells, but you can easily separate the shells using the Layout feature, as described in Layout UV shells.

Spacing between UV shells

The spacing between UV shells is an important consideration. You’ll want to have the UV shells as close together as possible to maximize the UV texture space. However, if the shells are too close together, there is the possibility that the textures may bleed between one surface to another.

Snapping UVs

You can use snapping in the UV Texture Editor to lock your transformations to existing objects in the scene. This functionality is similar to the snapping functionality in the scene view.

You can use the Preserve Component Spacing option in the Move Tool settings when transforming multiple UVs to maintain their relative spacing.

To snap to...	Hold	Icon
Grid intersections	x	(In the Status Line)
Other UVs (points)	v	(In the Status Line)
Pixels		(In the UV Texture Editor toolbar)

Note

If snapping is on and you drag an axis manipulator (as opposed to the manipulator’s center), the manipulator snaps to the nearest point or grid intersection restricted to that axis (depending on the snapping mode). Alternatively, you can use + x or + v to snap to the nearest point restricted by the U or V axis respectively.
Pixel Snapping is measured by monitor pixels. You can zoom in close to the UVs to achieve better results. This setting also affects snapping for rotating and scaling pivot locations.