Follow Focus CAD Model

About This Project

During the design stage of the big DSLR video rig project I have been working on I wanted to add some extra stuff into the 3D model of the baseplate that I designed.


I had bought a couple of professional video accessories; matte box and a follow focus, both made by Fotga which is a lower end Chinese company that sells some good and some bad products. I was really impressed by both products, the follow focus was all metal, mostly anodized black aluminium, with a nice magnetic polymer marking ring, and the matte box had an integrated top handle and swing away design.


I decided I wanted to model the follow focus first so I started off by disassembling the whole unit, cataloging the screws so they wouldn’t go missing and laying out all the parts on my workbench. The next stage was to fire up Autodesk Inventor, my CAD software of choice for stuff like this and got to work. The next couple of hours consisted of careful measuring of parts with digital callipers as I created each part of the unit working from the bottom, up.


After all the parts were modelled it was time to assemble the unit. I utilised three sub-assemblies for the follow focus unit; bottom clamp, gearbox and knob. Working with sub-assemblies makes constraining and fitting parts together much easier and removes confusion making the whole experience much more relaxing. Each part was imported into the respective assembly and fitted together using constraints. I like to constrain parts exactly how they would be assembled for real, so I predominately use insert constraints wherever a bolt goes etc. and only use the surface constraints to align the part if its not going to be fixed in that dimension.


It took me about 6 hours modelling time from start to finish, and I’ve only been using Inventor for about a year so I was pretty pleased with the result. Check out the renderings of the finished model and the time lapse video of me putting it back together again.