Cutting UV Seams on a Biped

originally published in 3DW 1xx

 

Video – soon!

Where to start cutting seams is probably one of the most commonly asked question by UV mapping beginners. As a UV map’s function is to provide flattened, well laid out and easy to texture mesh topology, it’s actually of lesser importance where you start to cut, than where your final seams end up, especially on a dense, non-symmetrical mesh.

You may want to start out old-school if you’re working on one of those, via cutting and flattening your unwrapping shells or seams first, and then refining, welding and reassembling your shells into a final map for texturing. Using UV Layout as an example application, we’ll cut unwrapping and welding seams and shells for a head and body.

You can grab Les Garner’s Behemoth.obj, which I used, from the UvQnA/Assets folder on the 3DW CD, or download it from his page here – and cut it into six parts: Legs, torso, arms and head: Do this by clicking on your figure to select it, moving your cursor over a polygon edge on each of the body-parts mentioned, and cut a seam by moving along the selected edge-loop, continuously pressing [C] as you go. Then press [Shift +S]. After you’ve cut the main shells, refine the cuts on the shells to make unwrapping and welding easier- For the head, cut seams for mouth, ears, and inner nostril-shells, and then cut a vertical seam through the middle of the head, around the face itself, and under the chin. This makes it easier to flatten the face, and weld it together again.

 

For the body, rotate your mesh so the back faces you, and cut a vertical seam on the torso, and a horizontal ones on the back of the torso, arms and legs, as shown. Refine these cuts even more, if needed. Also cut seams for hands and feet. Note that even if you don’t have a straight set of edges to follow, try to stick as much to the middle of the shell as you can, it makes it both easier to orient yourself on the mesh and keep track of seams.

 

Press [Shift +S] again. Drop each part in turn into the UV View by clicking on it and pressing [D]. Using the video on the CD as example workflow, unwrap each part by pressing [Shift+F] and/or [Shift+B] and Optimize, and weld them back into an easier to texture map by pressing [W ] and Enter. Tweak the flattening by using the Pin (P, 4,5,6) or Brush (R, Shift+ R, X, B) commands

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Tip: Press G in an empty space in the Editor view. Press F to select camera-facing polys. Press H, then G – it’s now easier to cut seams on a tangled mesh.