#3DTWIP 

I just love simplicity, I want to mention you can set dimensions with arimetic expressions like for example, the M3 head clearance to be lets say 3mm * 1.05, o r an addition, or also use variables like: (3mm * clearanceFactor) and then you can define those in the parameters dialog: forums.autodesk.com/t5/fusion-360-design-validate/global-variables-equations-and-dimensions/td-p/5306729 have fun!

I think the spool has to be on bearings, standard 608zz type, with thick sticky high-viscosity grease. This has helped me certainly with extrusion consistency, but i suffer from carriage compliance issues, while MK3 appears to suffer from moire-like issues, though possibly multiple other issues overlayed on top. The way distinctive lines have worked themselves into this print, i think it's worth trying for CRT!

It's just a hole, the screw cuts a thread

C.R.T yeah, I will ask toms3d since in his preview thumbnail picture for his prusa mk3 review shows a print with black glittered filament, thanks

C.R.T I found it I believe, it is called "vertigo grey pla" what do you think?

have not found it for less than 41USD, really expensive

The parts going whacky could be because of how things are dimensioned and dimensions moving from "20mm to the left" to "20mm to the right". In my experience this sort of stuff tends to happen when things are all dimensioned from a common datum (good for when you need to analyse parts and produce them manually) rather than dimensioned relative to each other. For example if you think about the volume knob, you can dimension the outer wall as a radius from the center of the knob, or as a wall thickness around the knob. In the first instance, you could change the pot dial's radius and it could end up being bigger than the volume dial and the geometry can shift unpredictably, wheres in the second method your volume dial would expand to compensate. It's all about how the changes cascade down the line. I learnt this the hard way in OpenSCAD where every constraint is use defined and there is no simple 'dimensiong'. If I referenced everything from a single datum, just about any change I made to the original sketch/geometry etc would turn my part into scrambled eggs, whereas if I referenced everything off the previous part it relies on/is mounted to or whatever, the changes would cascade down correctly.

SCAD is just a CSG routine though, it works on volumes represented as bunches of triangles. Everything is based on primitive source coordinates, there is no way to select a feature of a model and refine it further. In contrast, FreeCAD represents the model as vertices, curved edges, and curved surfaces. When you apply a sketch, it's applied to a world plane or a surface. When you apply a bevel or a shell or a fillet operation or anything like that, things that SCAD couldn't dream of, it's applied to a bunch of curved surfaces, and it can do a lot of advanced geometric math on them. The problem is, you select a given surface or edge or something - it stores the number of the generated edge or surface in the next operation that you perform. But these numbers are NOT stable. Sometimes if you go up the operation tree and perform the operation anew with slightly different dimensions, it will decide to generate the surfaces or edges in a different order, and thus their numbers change, and thus whatever anchored geometry you had, it will no longer apply properly. But this is the fundamentally elegant and correct way of working in FreeCAD, because this is exactly how you specify dimensions of things relative to each other there - its CSG lacks such functionality. I can make a model error-free and flexible in SCAD no problem, and if i mess up, i know how to refactor it easily, but making curved stuff such as fillets and bevels is extremely unpleasant to impossible, so its use is limited. The loft feature has been in limbo in SCAD for 5 years now! I should probably use SCAD more though. Or maybe i should rewrite it entirely from scratch, because i dislike so many fundamental decisions in it. Like the fact that there is no universal anchoring system, every primitive has a different coordinate system origin, or multiple but inconsistent. Relativity.scad is something that should have been core functionality, but since it's not, it has to rename all the primitives.

Off-topic: Is there a way to create a "linked copy" of object in FreeCAD? So that whem I modify one instance, all of them in the model change accordingly? I couldn't find how to do it and the manual only referenced static copy... Btw, I share your opinion on Fusion and linux :(

Robert, i think you're looking for "Draft Clone" function, represented on the toolbar - depending on version - either by a stormtrooper helmet in earlier versions or a blue sheep currently. There's also a "PartDesign Clone", which won't clone everything but can be used in PartDesign's CSG, while the other will not. Also i'm not an expert and am likely to get these things wrong. And yes, it's as confusing as it sounds, and makes FreeCAD seem like a hodgepodge that it is rather than a software that was designed for user experience first. (and yes, the icons were changed because someone was outraged on the Internet over incorrect use of their lore, because storm troopers and clone troopers are distinct from one another)

Robert Klauco, Just create one part then import that part multiple times into your assembly. That way when you change the original part all the imported instances update.

I mean it's not BAD. Maybe I'm just setting too high of a standard for the mk3. I have a ultimaker 3 at work and sometimes we get similar problems and it's a 3.5k printer.

I'd attribute that to it being a mendel/i3 printer and having to fling around the bed on the Y axis. It's pretty typical of these types of machines and the only way around it is to print slow, but prusa have been advertising the exact opposite with higher recommended/max speeds on the mk3.