Relative measurements?

[dgud]

You have the grid which is spaced out at 1x1wu as indicators.

If you select an edge, or two vertices the length is printed in the top left corner.

Otherwise it is hard to give information in 3D space, and you have the absolute commands where
you can move verts/edge/face to positions in 3D space.

In all textboxes where you input stuff you can write math expression as 1.0*3.0*pi()*sin(45)