Sweet Home 3D lets you draw sort of 3D drawings of your home or office.  I used it to do a virtual mockup of my house.

It’s a little finicky to use.  It works best if everything is flat on one level which my house is not.  There are small steps up and down into several of the rooms and the house itself is built into a slope with a walk out basement and I didn’t figure out a way to create the sloping land around it (yet!).  But it’s a fairly easy program to draw things if you are doing things which are not too complex.