2 questions. What is a shell, and what do the lines on a template mean?

[untakenname3453]

Hello I’m a New guy 

 

i recently bought a mesh avatar, and it came with these things called shells, which look exactly like the normal avatar, but the creator said they would help with cloths fitting to the mesh.

 

My other question is about these lines that appear on the avatar template. What does the colored lines mean? The green haze?

[Wulfie Reanimator]

I'm going to assume that the "shell" is a "dummy file," which is a simplified version of the mesh body. Simplified to prevent you from just uploading the mesh body yourself and having a full-perm version of the real product. It exists to help you make and rig clothing for the body in a way that approximately matches its shape.

The colored edges on that texture show where the seams are, and which edges connect where. For example, the left side (red) of the torso wraps around to the right side (red) of the back. The green "haze" on the outside of those colored edges ("minimum bleed area") is there to show you roughly how far you should color the skin, to prevent different shapes from causing the "blank space" of the texture to show up on the mesh as it changes scale.