Hi @slurton
I don’t think there is a way to specify a size in units. However, you could adjust the size by using the Scale tool. When selecting this tool, you can specify a multiplier in each of the X, Y and Z dimensions. It isn’t perfect, to be sure.
I will consider adding some type of unit-based sizing functionality for primitives (such as plane, cube, sphere, etc.) in my next version of MudKit. I think this could be helpful.