The seam guides are also known as a UV Map.  A UV Map is a 2D Representation of the surface area of a model.  It will tell you where each vertex related to another, in 2D.  

You can load any Figure/Model, into UV Mapper (A Free utility) and generate a UV Map.

This is how; Texture(usually skin but clothes/skin too), Transparency, Dissplacement, and Bump Maps are made.

To make the White Lingerie outfit, in this link; I just opened V3's UV in Photoshop, drew out a Transparency, and then applied it with the Material Room.