I was looking for a program to design a unique building and came across Sweet Home 3d. It has an installer for Linux that when clicked gives you the option to install or extract. I extracted it to a storage partition on another drive, clicked the app and it fired right up. It is simple enough that I could understand most of it by just playing around.
71.1mb zipped. 148mb extracted to a folder, (Not sure how much I added before I checked), and runs great in fossapup64.
It is very versatile and the options are amazing.
You can get it at http://www.sweethome3d.com/download.jsp
You can import all kinds of models, textures etc. I haven't even scratched the surface of what it can do. They have a great community and tutorials in the how too section plus where to find just about anything you might want to use in the program.
Warning! it can be very addicting.