[adaptive tesselation]

want/need this.

Subdivision preview modes!

[Retopo room: Switch between transparent and solid mesh view]

A subdivision preview would kill the workflow. It is only interesting, after Andrew have implemented a multicore support for the retopo tab - as long as this is not solved, a subdivision preview will need too much cpu time and is currently not practicable.

Why do you need a subdivision preview? Give an example.

When you want to have a non subdevided object for say, cinematics. You want the base mesh to be very low polygon and increase the sub-ds as the camera gets closer. you care less about how the base polygon mesh looks but want the sub-ds to look good.

This also applies to hard surface modeling. Have a very low base mesh.