Make mesh watertight

With the t-shirt shape finalized, make your mesh watertight by "sealing" the holes at the neck, waist, and wrist. A watertight shape ensures that only the top visible surface of the mesh is exposed at any angle. If an asset is not watertight, it may expose backfaces (single-sided faces) that could affect the rendering of your asset and performance when equipped to a character.

Watertight top view
Watertight bottom view

To make your t-shirt watertight:

  1. With LongSleeve active, switch to Edit mode.

  2. Starting with any hole in the mesh, hold Alt and click the last edge on the mesh. The entire edge highlights.

  3. Press E to extrude the mesh, then click after a small extrusion is added.

  4. With the new edge still selected, right-click and select Merge Vertices > At Center from the contextual menu.

  5. Press G to grab the new vertex and reposition it within your t-shirt mesh.

  6. Repeat until all the interior-exposing holes of your mesh are closed.

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