X-Wings need their trusty astromechs! I wouldn’t be surprised this whole project started because Jason got enamored with the Bandai droid kits. And actually, because of these kits, we didn’t really need to model the droids for the 1/12th scale model. It would be nice to have them a) for reference when making the CAD though, and b) for the 1/24th scale fleet.
Fellow GrabCAD user Dape has a nice collection of droids available. We used their R2 and R5 units nearly verbatim as reference. I did crosscheck a few things against what’s available on Astromech.net for accuracy.
What we didn’t find was a good R4-unit CAD reference. I’ll talk about our R4 in a bit, but first, here’s our droid line-up (forgive the liveries – they are just placeholder. Jason will nail the paint jobs for sure!).
Modeling the R4 Head
The head is a lot more nuanced than it first appears. Here are some failed attempts at modeling it. We saw quite a few that took a multi-panel design approach. Mixing cones and flats in some sort of inverted-sharpened-pencil effect. Looking at all our photo-reference, showed this was not the right way to go. It is way too mechanical.
So if geometric construction wasn’t the approach – maybe it was something more sculptural? Lofting six surfaces from flats (each edge at the hex end) to arcs (at the circular base) and blending out the seams was more interesting for sure.
In fact, we think this is how the Bandai 1/12 scale kits were modeled in CAD. We also don’t think it’s entirely accurate. You get very strong linear highlights from top to bottom, and we just weren’t seeing that in the real prop droids used in in filming.
Next was using a straight-forward loft from the circular base up to the soft-hexagon at the top.
Just letting the computer spit-out a shape was closer to what we thought we were seeing on the forms, but if you look at the way the highlights spike from top downward, it still didn’t feel right. But it gave me another idea.
We have it on good authority that the R4 heads were made from a cone that was then tacked/glued into shape at the top. So it was a cone that was deformed into a hex at the top.
We have tools for this! Maya can simulate pressure being exerted on a soft body. Used in everything from CG cloth to pod racers crashing spectacularly, it seemed like a good use of dynamic simulation.
Our truncated cone had an upper circumference equal to the perimeter of the hexagon shape we were targeting. Pressing inward on the six faces simultaneously pushes out the corners and distributes the forces evenly down the length of the part.
Using plastic deformation to model that shape got us the closest to what we think the shape actually was.
While very similar to the simple loft, there is a softness to the blend that we didn’t have before. The highlights feather-out in a more aesthetically pleasing way.