Modeling Software?

Who knows better than you what your needs and capabilities are.

Why not download some and try them?

3D Model Download,Free 3D Models Download

thanks but even simpler than that. A 90degree equal angle 0.5m long hinged to another...so the software to make/draw it then animate it with different hinge points...gs

Free 3D

If you are keeping it really simple, you can do this in AutoCad 2D for simple shapes. If it's a rectangular block on a hinge, that's all within the capabilities of 2D CAD. You have to look for the interferences rather than have the program find them.

If you want more, you gotta go up that learning curve.

I have been using designcad3D MAX for years. it is not free but it is cheap less than 100.00 USD. it is excellent and fairly simple to use. Check it out!

Some alternatives:

Blender (more for the artist than the engineer, but extremely powerful- used for making commercial animated films)

Salome (developed as a front end to FEA/CFD analysis- easy, straight-forward geometry and meshing capabilities)

BrlCAD(developed by the US Army Ballistics Research Laboratory, for obvious applications. Steep learning curve, but fits your criteria quite closely)

FreeCAD

All Open Source (and free, by the way).

You may want to have a look at a summary I put together here on Dropbox with more detail and discussions. There are a lot of comments by others on the subject on my blog here on CR4 that you might find interesting.