What are some alternatives?
When comparing EQUINOX-3D and SelfCAD, you can also consider the following products
Maya - Maya in Launchpad
PathEngine - PathEngine is a middleware toolkit for the implementation of intelligent agent movement, built around and implementation of points-of-visibility pathfinding on 3D ground surfaces.
MilkShape 3D - The MilkShape 3D website has been down for almost one week.
Autodesk Tinkercad - Tinkercad is a super easy-to-use, browser based 3D design tool.
Cinema 4D - Cinema 4D is a 3D modeling, animation, motion graphics and rendering application.
SketchUp - 3D for Everyone