In a SBC it is hard to do real-time stuff but there is access to the much faster processor and far more advanced cores and arithmetic logic units. This makes it possible to add more shaping into the input for directions. So each axis can move very quickly near the limits of how fast the physical hardware is capable. The calculations are made to ramp the speed up and down in ways that a little 8/16 bit microcontroller is incapable of achieving. This is also why printers with a 32 bit micro are a little faster as well. The microcontrollers used are like 16-72 MHz but there is no overhead like with an operating system. However, they are also running the PID control algorithms for the bed and hotend. You need both a SBC and a microcontroller unless you get into super niche setups. OS kernel configurations have issues with real-time tasks due to some of the ways kernel space is abstracted in an OS and how the CPU scheduler juggles running process threads and interrupts in the OS and hardware. People do not typically mess with a SBC on this level like adding core isolation with a dedicated thread with the CPU scheduler set to real time. There are other potential factors like core spin up, temperature, and power management that need addressing in the kernel too for RT. This is as far as I understand it, as this is a curiosity I’ve barely scratched the surface of a few times. Hopefully this abstract overview kinda helps.

Think of a microcontroller like a simplified computer from the late 1980s. It is about like an original Nintendo Gameboy but all the extras like memory and RAM are built into a single little chip and the architecture is simplified a little bit. Something like a Rπ SBC is about the same class as a 10yo smartphone. It is actually a TV set top box tuner chip with all the set top box stuff ignored and undocumented.

Marlin is like Arduino firmware. It is just a project that is well organized and setup with an extensive configuration menu about like configuring the Linux kernel. You are prompted with options and you select what is relevant. This is then compiled in a Makefile and you upload the binary to the microcontroller just like an Arduino. The software is setup to make it easy to add similar hardware and maximize entry points so that you can try novel stuff. Unfortunately, Prusa does not run Marlin like this. They are on their own branch of Marlin that specifically makes it difficult to configure and make changes. It also makes cloning a Prusa impossible in practice because they can make changes that will break compatibility. This is the underlying reason the real hobby hacker community that originated around RepRap and the MKx name moved to projects like Voron. The limitations and changes to Marlin were due to Prusa not wanting to break upgrade compatibility and sticking with the AVR microcontroller all the way up to the MK4. They pushed the micro really hard to do both the printer and multi material stuff along with all the fine tuning. So that is kinda the legacy reason for how things evolved.

Personally, I don’t care that my printer is a slow MK3S+. It works well without ever doing a calibration any more and I can print PLA, PETG, TPU, PC, and PA/ABS/ASA with a few caveats. I don’t run my printer 24/7 or even daily, so I am slower than the machine.

I got a little Kingroon KP3S to mess around with Klipper and see if I wanted to build a Voron. I decided not to. Running Klipper means you must setup and dial in all the fine tuning details that Prusa is doing for you with the original firmware. You lose the it just works factor. That is totally fine if your priorities align with this methodology. The KP3S is capable of running Klipper on the original board after just adding the Rπ and loading the firmware. That is probably the cheapest half decent way to mess around with a project printer in Klipper. I never use the thing though.

Also, spline:

Blind dove:

And Book “The Complete Guide to Joint Making” by John Bullar – at you (not recommended or anything, I got it for a few bucks back when Better World sold stuff dirt cheap on eBay):

Also @OP: if you’re using PLA, I have heard good things about Weld-on 4 acrylic adhesive.

Generally, I consider something to be dystopian if it is making negative assumptions about the future that are rooted in speculative fiction. These are more like science fiction, fantasy, or geopolitical.

I consider something utopian when it is unrealistic and glossing over aspects that are impossible or poorly premised while presenting them as positive.

An example of dystopian would be the Terminator films or most films and books about AI. These fall into a trope of the machine gods. These are no more than a retelling of a pantheon like mythos of supernatural gods. The issues of future AI are unrelated to this mythos. They are also based on the fallacy of dominance caused extinction. By this logic Earth is a monoculture. These conceptual abstractions are dystopian because they are making stupid handwaving assumptions that result in a dark and grim setting.

Depicting the messiness of reality does not mean a fictional story is either dystopian or utopian.

An example of a utopia is something like a biblical paradise. It is premised on brutal authoritarianism that lacks any objective nuances about the true diversity of life and opinions. It is glossing over the real differences in what people want and expect out of life in an idealized story arc that harms a lot of people. When these people are sidelined as irrelevant, the true underlying dystopian reality comes into view. Utopia is always a story of propaganda-like perfection masking a terror that lies beneath.

One can paint such abstractions on almost any story. These are not really genera even if someone calls them such.

You mentioned your story involves massive geopolitical upheaval. This concept could be painted as dystopian depending on how you write it. Throughout history there were many underlying reasons for changes. Like in the era of Alexander the Great, the conquests of the Macedonians in that age were more due to advances in equipment and a professionally trained army in an era that primarily consisted of less formal city states and small raiding parties. The era of the Romans was mostly the beginnings of broader social cohesion and coalitions of regions. The Great War and WW2 was the era of solidifying global boarders and the role of imperialism. If you are proposing a new era of evolving change, the reason for that change and why that change is a form of evolving progress in a geopolitical sense is important if you would like to abstract a label of utopian or dystopian. Otherwise it sounds like “war fiction” IMO.

The main trick to calibrate touch is Wax and Grease Remover (a solvent). When W&GR is used on a panel it will briefly form a wet gloss. That wet gloss will simulate what the clear coat will look like but slightly worse because a 2k clear is much thicker and will level.

When sanding anything from fillers to high build primers, guide coats and sanding blocks are what matters. Blocks must be wide enough and shaped to bridge the issue. With most regular jobs that don’t require absolute perfection, curved surfaces are sanded by hand using a soft foam block.

Back in the day, I would have loved 3d printing and TPU because I could have made custom sanding blocks for jobs. Back then I used balsa wood to make special shapes when I needed them. I had probably three dozen or so sanding blocks for all the different issues I came across.

For guide coats, some people like a graphite like powder that is made for guide coats because rattle can enamel is absolute garbage paint and leaving any of it behind is a major risk under urethane paints especially the color coat. However, I still only ever used whatever junk rattle can I found on sale for a dollar. You only need a light speckled but consistent dusting of a guide coat. The sanding block will show the highs and lows. Just be sure you’re using the block like a rolling pin and not like a scrubbing brush. You can even use a guide coat with sanding prep for polishing work.

There is not a ton of skill in this area. A few tips about techniques is all it takes. The real skills of automotive paint are in tinting colors to match the degradation of an existing finish, matching orange peal, and primarily knowing how to best remedy situations when things go very wrong. All the various ways paint can react badly are complex problems and those lessons are hard won with bad experiences. Most can be avoided with meticulous cleanliness at the earliest phase of work.

I don’t do well with very long project timelines. I think it is quite remarkable that you can last for 5 months on a project with kids and all the distractions that entails. Sleep deprivation puts me in situations where it is like my mind is wiped every couple of months. I just don’t care to get back into a complex project and lose my motivation to some new curiosity. I tried to fight it at first. I was only like this after disability. It just becomes a depressing spiral and I don’t tend to finish very much. Hopefully that changes. I have several nearly completed projects I would like to finish, but oh well. Kids would absolutely drive me nuts, but I am at pain levels with sound and some light sensitivity 24/7.