Unfolding a UV mesh

Unfolding a UV mesh is the process of cutting a mesh so that you can lay its entire surface area flat. However, before you do this, you want to make sure your UVs are spread out evenly along the surface. You can do this by applying a basic checker pattern to the mesh.

To apply a checker pattern to the torso

1. -click the torso and select Assign New Material from the pop-up menu.

   The Assign New Material window appears.

2. Select Lambert.
3. Open the Attribute Editor.
4. In the lambert tab, set the lambert field to checker_pattern.
5. Click the box next to Color.

   The Create Render Node window appears.

6. Select Checker.
7. Press 6 to enter Smooth Shade mode.

   The torso is covered in a checker pattern.

   
8. In the panel menu, select Panels > Perspective > persp.

From the front view, the checker pattern looks roughly even with very little distortion. This indicates that the spread of UVs is fairly even. An even spread of UVs is important to avoid texture warping when you apply your texture. In some cases you may need to experiment with different planar mappings to give you the best base to start with.

However, the planar projection isn’t perfect. If you look at the sides of the torso, from the armpits to the waist, you can see some warping. This is the ideal place to cut the UV edges for unwrapping.

To cut the UV edges

1. -click the vest and select Edge from the marking menu.
2. Select all the edges in the line that runs from under the arm, down the side of the soldier’s body to the bottom of the vest. You can do this by double-clicking edges along this path until they are all selected.
   
   TipThere are many small edges that must be included in your selection. Dolly, tumble and track the camera to see the edges on the underside of the belt and in the underarm region.
3. -select the corresponding edge on the other side.

   An edge loop on both sides should be selected now.

4. In the UV Texture Editor, select Polygons > Cut UV Edges.

Now you are ready to unfold the mesh.

To unfold the torso

1. -click the torso and select UV.
2. -select one UV at the inside tip of each vest strap, along the unfold line.
   
3. In the UV Texture Editor, select Polygons > Unfold > .

   The Unfold UVs Options window appears.

4. Select Edit > Reset Settings.
5. Set Pin UVs to Pin selected UVs.

   A pinned UV does not move when a UV mesh is unfolded. In general, you want at least one pinned UV when unfolding because it gives the unfold process a point of reference. This is similar to placing a pin in a piece of fabric so that it does not unfurl out of control as you unfold it.

6. Click Apply and Close.

Maya lays the UV mesh out across the UV space. Parts of it may fall outside the 0-1 texture space, but that’s fine for now. More importantly, notice that the pattern is much more even across the mesh now.

Unfortunately, while you’ve minimized the distortion, you’ve also create a visible seam where you cut the UV edges. Unfortunately this is unavoidable. In general it is best to put your seams in the least visible places. In this case, the seams will be obscured by the arms most of the time and therefore won’t be as noticeable.