Fighting with computers

I have been playing with CNC machines for a while and one idea of improving their performance came to my mind: what if, like they do with processors, we could add some parallelism to the process to get more work done in the same amount of time? So a multi-core processor will be the analog of a CNC machine with several spindles. As usual, a quick look at the Internet reveals that a "dual-gantry CNC" is not really a new idea as a few videos can be shown on youtube from some commercial units . Interestingly enough, there are just a few cases shown, which makes me think it is either a bad idea or too complex to work properly in most cases. My plan here is to have two gantries that move independently and to follow the RISC approach: I will handle the dependencies in software so I will create to g-code files, each one feeding one of the gantries in a way that both gantries planing contains no collisions. I guess another approach could be to put in place some kind of collision

A couple of details made me waste some time till I figured them out. First one was an issue with povray 3.7 running on Linux that would preview a black background when I wanted a transparent background. Output was a PNG file and the final result was ok, but I failed to notice that there was an error with the command temporary output to the display and not with the final rendered file. I noticed the problem once I ran the same command with the same files on my Mac and preview shown the checkered pattern of a transparent background. But this does not mean the Mac versions are any better: Second problem, using Meshab 2016.12 version it was impossible to get a snapshot with a transparent background either. It appears it is a known issue too.  Same version of Meshlab but running in Ubuntu worked like a charm. I had a third problem I can only blame myself for: it turns out STL files and Povray use a different coordinate space, so my renders appeared flipped horizontally. Nothing that