Using your modeller’s mirroring or symmetry function while UV mapping is one of the best time-savers around, read our guide for using it in 3ds Max
The basic technique is the same whether you’ve created a hard-edged or organic model: split your mesh down the middle, delete one half, map the remaining half, and mirror the mesh.
Depending on complexity and texturing requirements, you can keep the UVs stacked, or flip some or all shells. When you’re done mapping, you can tweak both mesh and texture, if needed, to make it look less symmetrical.
Although 3ds Max is used for this example, the principles apply to other UV-capable 3D packages.
01 Set the scene
Regardless of whether or not your starting point is a box-modelled mesh, ensure a clean start by having a half-mesh to start working with – either by splitting and deleting it down the middle, or simply deleting your current instance or Symmetry modifier.
Unwrap your mesh. You can use either 3ds Max’s native tools or an external UV mapper as you prefer. If you know the shells will need to be flipped or stitched due to texturing considerations, try placing the unwrapped shells in only half the UV space (0>0.5); having everything laid out in advance will make subsequent UV work much easier.
02 Apply the modifiers
Select the mesh, and apply the Symmetry modifier from the Modifier List dropdown. Set your mirror axis to X and untick Slice Along Mirror to avoid the mirror gizmo in the modifier acting as a Slice Plane. Leave Weld Seam ticked to weld vertices along the middle.
Sometimes the default setting won’t catch everything, so increase Threshold until most gaps are welded. Also consider doing manual (Target) Welds if the gaps are too big, as Symmetry Weld sometimes creates ugly welds. Add a UVW Unwrap modifier on top of the Symmetry modifier. The UV seams will now display.
03 Fix the flips
Your UV shells are now stacked on top of each other, and textures will render flipped on the other side of the Symmetry modifier. You can fix this by first unticking the Weld checkbox in the Symmetry modifier, to select only half the mesh, then going to the UVW Unwrap Modifier. Here, select Faces and tick Select by Element in the Unwrap UVW rollout.
In the same rollout, click Edit under Parameters to access the UV Editor. Select Tools > Flip Horizontal in the UV editor menu to flip the UVs so the texture will render correctly. Go back to the Symmetry modifier, and check Welds to turn welding back on again and restore the entire texture. Stitch and tweak any UV shells as needed to finish.
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By Cirstyn Bech-Yagher
3D freelancer
northern-studios.com
Posted on Thursday, July 14th, 2011 at 2:48 pm under Guides, Tutorials. You can subscribe to comments. You can leave a comment, or trackback from your own site.
Tags: 3ds Max, tutorial, UV mapping
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