by Deutherius

I love The Expanse and always wanted my own Roci. After a bit of searching, I found 3 models of particular interest
1) The low poly"The Expanse - The Rocinante"bySYFY
2) The beautiful"MCRN Corvette Expanse"byurbanenomad
3) The absolutely bonkers detailed"Rocinante fixed/sliced"byMorganCoLLC

The first one is a little too simple for what I wanted. The third one, on the other hand, is way too detailed, with parts that simply wouldn't print on my FDM printer (especially the PDC cannons and antennas). Not to mention that AFAIK the original model was made for renders and had tons of open geometries - Morgan managed to fix most of the model (mad props btw), but the front part of the ship still refuses to slice correctly for me as of april 2020 (giant hole where the PDCs would stow). I tried fixing it manually but gave up really quickly.

Urbanenomad's model, on the other hand, has just the right amount of detail, printable PDCs and antennas and no significant mesh errors. What I don't like, however, is that the model is hollowed out, which is a problem especially with the exhaust section that has a gaping hole in it. It also doesn't help printability much since you need to support the internal geometry when printing. The hollowing also doesn't help when you want to print the ship in parts and glue the parts together. There are also some unavoidable overhangs that need to be supported. Finally, the stand also has two small problems - it only fits the sleek version (PDCs hidden) and cannot be downscaled too much - the "THE" in "THE EXPANSE" starts to be unprintable even at 70% scale with a standard 0.4 mm nozzle, disappearing completely at about 55% scale even with "thin walls" in Cura enabled.

So, the changes I've made are as follows:

1. Deleted the internal faces of the MCRN corvette and closed the geometry at the exhaust section for both sleek and PDC version of the ship

2. Added the inner drive cone structure from Morgan's Rocinante

3. Separated the ship in parts for optimal FDM printing

4. Added unique keying to all parts so they are easy to assemble and glue together

5. Increased size of the "THE" lettering on the stand

6. Derived a second version of the stand for the ship with PDCs open

The new Roci now has 5 sections:

1. Drive (same for both versions)

2. Connection plate (same for both versions)

3. Back section (sleek and PDC version)

4. Mid section (sleek and PDC version)

5. Top section (sleek and PDC version)

All parts are already oriented for optimal printing. No supports should be needed for the Drive and plate sections. The Top and Mid parts require minimal supports under the bottom vents (and even that is optional for the mid part). The back section has vents on the bottom - set up your slicer to print them as bridges (horizontal and vertical lines, not diagonal) and they will look like awesome vents when done (In Cura, you can do this by going into the Experimental settings and playing with Bridge Settings - lower the Minimum Bridge Wall Length and crank up the Bridge Skin Support Threshold - I got mine at 4 mm and 90 % and it works like a charm). Supports can help, but are, again, very minimal.

PDC versions obviously require extensive supports, I had decent success with Cura's tree supports.

6 keys are needed for the full ship. The keying positions have unique offsets between parts, so the model should only go together in one way and look even remotely right. They have a 0.3 mm tolerance at full scale, you might need to experiment with different sizes depending on your printer, especially for different scales of the ship (for example I had to print them at 47% scale for my 50% scale Roci to fit comfortably). They are not made to pressfit and hold the ship together, just to aid in gluing the parts together.

So far I have successfuly printed a 100% scale sleek version, 3x 50% scale versions (2 with PDCs, one sleek) and a 25% scale sleek version, all of them in parts and glued them together. The 25% scale was a bit of a PITA, but it is possible.

Work in Progress, all criticism welcome.

Incoming Soon-ish:
I am currently working on standalone printable PDCs, so if you decide that your awesome Sleek Roci is not threatening enough, you don't have to print the whole thing again. Printing the Roci with PDCs already on there can also be support-intensive, printing individual PDCs is way easier and requires minimal support and cleanup.

Print Settings

Printer brand:

Creality

Printer:

Ender 3

Rafts:

Doesn't Matter

Resolution:

0.2 or better

Infill:

~15 % for full scale with 3 walls