Here's a PV report on how to create 3D composites at 4K quality using a tool chain consisting of 'free to use' or low cost tools:

I've made myself a goal of creating a short worthy of presentation at a film festival. Basically because creatively it is the next step up from corporate videos. It's actually very hard to do, I've put more than 1000 hours in an have virtually nothing to show for it. However this long weekend has allowed me to get a whole pile of tests done and even have the 3D printer running for a few hours.

I've built this 'studio' in a spare room and I'm going about dealing with the challenges of video is a small space. Audio has been a bit of a challenge, I've been adding tiles to the ceiling in blocks of £90, and that doesn't get you many tiles!. Ikea has been my friend in terms of cheap deep pile rugs.

I've purchased Fusion Studio so that I can get access to the proper version of Primatte (Keying). I'm just getting my head around keep-out mattes which you can see connected to the garbage matte below (two Primattes, one to key the other to build the keep-out).

Here's a few seconds of bringing a pile of stuff together, It's a Fusion composition where the background is created in Cheetah3D. The interfaces are procedurally generated:

I've found that I can export of the video as a series of transparent PNGs that can be imported into Motion and FCPx It cost me £69.95. I'm going to use it to combine 3D elements in Motion for titling and concept animation sequences.