jruiz wrote: ↑
Fri Sep 14, 2018 9:55 pm
I propose that you do a little mental exercise with the help of another person who knows about Cartesian coordinate system but with no notions about any CAD software
Let me try to convince myself I know nothing about CAD for a moment. Of course, it's not going to be perfect, but here's how I feel about it:
That is, Z is up (that's for sure!), X is to the right, Y is forward. For X,Y, I would choose them like that, because if I draw a coordinate axes on a sheet of paper and put the sheet onto the dashboard, that's how they orient.
I spent quite a bit of thinking when choosing placement marker for Lattice workbench. It was obvious that the straightforward indicator "axis cross with color-coded axes" is very difficult to interpret. It takes effort to recall, which color is which, and the orientation of the whole thing is often not quite clear by just looking at it, I have to give it a spin to pick up the actual 3d placement.
So eventually I arrived to a paperplane shape, because it's easy to remember which axis is which, and easy to quickly get a clue of how it's oriented.
The choice "X axis is direction of flight" was quite natural, but I think I even looked up conventions in aviation, just to be sure I won't have to remap them later when complaints from experts arise.
I think, it is quite important to stick to a fixed convention, at least because of this. Having a switchable convention for my paperplanes is simply not portable.