2D/3D visulaizing tools

I am trying to understand positioning in 3D and was looking for some simple ad free tools to understand how things work in positioning algorithms.(Or how to visualize the positioning)

I came across some really fascinating software:
Archimedes Geo3D - probably the best software out there for 3D visualization
Geomview - allows one to manipulate images in it as output from other software.Has a messy installation though (could not install it as openmotif could not be successfully configured on my Ubuntu machine)
GeoGebra - free java based 2D geometry software.