OK, so I have it working. The black areas on the alpha sheet are aligned with the endcaps of the model everywhere a part can break off. All of them are working except the wings. Wing a wing comes off, the associated damage decal shows up, but only with the clean line of where the model breaks, and not the jagged edge I made in the alpha sheet. When the nose is shot off, it displays its decal and alpha correctly, but also claims the alpha from the wing break, though it doesn't show the wing break decal. Any ideas how I can get the wings to claim their damage alphas?