Mini R2D2 build - head shell modeling

Like I said in first post I'm new with 3D modeling and not going to write everything I did in Fusion 360. I'm going to talk about generally what I have done and what worked on my model.

First thing was to decide diameter of the shell. I already did my first draft with 140 mm and 4 mm shell thickness. Somehow that didn't feel right. Wall was too thick, at least it felt that way and our printer can do up to 190mm prints so why not give larger a go. We are installing automatic print leveling with distance sensor in future and that will take off few centimeters. To give that room I decided to try 150 mm and 3 mm thickness.

Droid head will have shell, neck upper part and panels. Also there will be few panels that have some accessories on. Those will be drawn individually. Shell will have 1 mm recess and 2 mm shoulder where panels can be clued.

Scale

Blueprints from Astromech are in inches. So I need to scale my model from those. Blueprints gives life size R2D2 dome 18.250 inch diameter and I have decided my droid to have 150 mm diameter dome I can scale my model directly from inch. 150 mm / 18,250 inch is factor of 8.2 rounded. So every measure can be multiplied with 8.2 and I get millimeters. It gives me fractions so I decided to just round it into nearest millimeter.

Model Components

First draft taught me that everything you want to print separately needs to separate objects. So when I started again this time with middle point of bottom ring of shell is at origin and made sure that I'm only modeling the shell and nothing else. This will give me also possibility to hide some parts if needed.

Also I can make servos and motors components and I can fit those inside to their place. This also gives possibility to test if everything fits and there is enough room for parts to move.

Top panel holes

Top holes blueprint had radius for all the rings and distance between panels. So I needed to start doing some trigonometry. There are one round panel in middle and six panels around that. I had starting angle from one panels middle point and from there I calculated that every panel with spaces between was 60 degree angle.

R2D2 head shell 3D model top holes

These can be done by creating the shapes on top of the some and extruding till the bottom side of the dome. Sholdes was extrduet till top side and then putting 1 mm offset.

Side panel holes

These are tricky to do. Fusion 360 has principal to drawing should be done on a objects plane or the original plane. And the dome is not a plane on that standard. I decided that best way would be to create holes as separate panels and then moving those into to the shell and then combining those with cutting. This took me two nights to discover and one evening to practice to do those panels that has the domes shape and half of that how I figured how to work efficiently.

These took me 3 nights to make. But I learned how to do those!
R2D2 head shell 3D model bottom holes

Bottom ring

Bottom of the head is ring that is small cylinder. I decided to keep it separate to reduce print time if needed.
R2D2 head shell and ring 3D model
Now it start to look like a R2D2 head.

Ready for 3D print

I think I will test print this and see if there is any problems. Shell should still have some mounts for servos and hinges (if I can fit those to open some panels). If I wait until I get those fitted in there might be more problems when I print this.

I have printed kind of small objects before and I was expecting long print time. But not 20 hour with supports. I have to play around with printer and try different layer heights. I will be sanding the final product so hopefully this won't affect that much on on the quality. Will see.