Computer Modelling in 3D

A Russian model of an American tank.
Universal Mechanism's model of an Abrams m1a1 tank, for detailed analysis
of track and vehicle behaviour over uneven terrain.

A good 3D modelling program

After some months of looking around for a good 3D modelling program, I decided to go with Universal Mechanism (UM). This program is under active and ongoing development by Prof. Dmitry Pogorelov and his team at Bryansk State Technical University in Russia. The website for English-language visitors is http://www.universalmechanism.com/en.

There are many YouTube videos posted by UM of simulations using their program (just search for videos by uploader universalmechanism) but these are all very short — too short to really show what the program can do.

Although there are other 3D modelling programs which are no doubt very good, the main reason I chose UM was that, unlike most, it clearly does cater for private individual users. The price for UM Base (the full program) is a very reasonable $150 US for an individual user. Additional specialized modules can be purchased as desired. UM's pricing schedule is at  http://www.universalmechanism.com/en/pages/index.php?id=11

UM Base can be downloaded for a decently long free trial period (a total of two months, from memory).

There is also a "lite" version, UM Lite, which is always free for an individual user, but I found it was too limited for my purposes.

Universal Mechanism's model of a spinning top.
Here, UM chose to build the model up entirely from parametric equations, rather than from a drawing.

Learning curve

As with any other program, there is a learning curve, which can be a bit steep at first, but worth it. Still, I have a long way to go to become really proficient. I'll give just one tip at this stage:—

I find it easiest to start building the model as a 3D drawing in a CAD program, and import it into UM as a .3ds file. Saving it again as a UM CAD file converts it into the .ucf format UM requires. With this approach, provided the model is not too complex, it may be easiest firstly to create all objects at the origin (0,0,0), and then to use the coordinates of the joints connecting them to place the objects correctly in the model.