This week, I've started working on the paper tape reels which are held in the base of the SG-41. Two tapes can be fitted; one for the cipher text and one for the plain text to be printed. @tnmoc.bsky.social @threejs.org

We are getting so close now! This week sees the completion of the final part of the actual SG-41 mechanism; the ink cartridge & upper paper feed rollers. So is that it ... all done? Not quite, there's one important part missing. @tnmoc.bsky.social @cryptomuseum.bsky.social @threejs.org

Virtual Schlüsselgerät 41 (SG-41). Another week and yet another mess of levers in the CT scans that do something .. but what? One of those cases where I'm just going to have to model & animate them in @blender.org & @threejs.org to find out. @tnmoc.bsky.social @cryptomuseum.bsky.social

It's time to fill out some of the metalwork that holds everything together. It's no wonder the SG-41 weighed in at around 13kg especially as Germany were running out of lighter metals by the end of the war.
@cryptomuseum.bsky.social @threejs.org @tnmoc.bsky.social

One of the final external controls completed, the F/L knob. This switches the SG-41 between Funktion (Operate) and Löschen (Clear). Clear mode releases the mechanism from the cipher wheels so they can be moved to a new position or reset. @tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

Last month, I was thrilled to be invited to GCHQ in Cheltenham to see their rare SG-41 cipher machine for real!
It has answered many questions about this amazing WW2 machine. I can now move on & complete my latest sim which will be released (hopefully later this yr) on my site virtualcolossus.co.uk

I've been continuing work on the paper feed mechanism after a very exciting visit which has helped a huge amount (more on that soon). The paper feed lever allows you to extract your printed cipher/plain text from the SG-41. @tnmoc.bsky.social @cryptomuseum.bsky.social

As well as working on modelling & animating the complex paper feed mechanism, I've been having a play adding a few extra visuals. Some useful (hiding specific parts of the mechanism to see how it works) and some just eye candy!

@tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

I've added the letter counter to the SG-41 this week so take a look at how that works. Also, I've animated the folding handle so the machine can be packed away for travelling.
@tnmoc.bsky.social

I broke more than fixed this week! I'd placed a few items in the machine out of line so last few bits didn't fit. I re-checked the scan so all fixed now!
The question to answer today - "What happens if you run out of paper?"
@bletchleypark.bsky.social
@tnmoc.bsky.social
@cryptomuseum.bsky.social

Lots to show you today for Virtual Schlüsselgerät 41. Working out the print mechanism meant going back to uncover the cage drive works in detail! New drive mechanism, the print wheels working and switching between encipher/decipher. Phew! @tnmoc.bsky.social

Adding in a few shadows make all the difference to a simulation. This is made very easy with Three.js which is the JavaScript library I'm using for 3D.
The encrypted output is not from a coded sim, it's from the mechanics alone!
@tnmoc.bsky.social @threejs.org

Now we finally get to see how all the messing about in Virtual SG-41 with cogs & cams starts to encipher our letter. A lot of work done in past couple of weeks to get here, this is a fiendishly clever device!
@tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

Our Virtual Schlüsselgerät 41 was looking a little naked, so this week, I've been modelling it something to cover it up.
This really adds so much to the look of the machine, looking awesome.
Still lots to do, so keep following along.
@tnmoc.bsky.social

Now we've got the Pilot ACE completed, it's time to get back to our build of the SG-41 (Schlüsselgerät 41). Here's a very brief recap of where we'd got to and a quick additional set of levers hidden away behind the rotors to work out. @tnmoc.bsky.social @cryptomuseum.bsky.social