[FR] Automatic Extrusion

I’m not following you here and especially not on this arc argument.

In my opinion, arcs is one of the least understood, least needed and most overrated function ever.

Lets start with the obvious:

Most printer kinematics cannot follow a true arc since they work with discrete X and Y movements.
There are very few (one? → SCARA) kinematics that could even do a true rotation and, as far as I’m aware, they are today not smart enough to take advantage of.

Worst case workflow

The following workflow was true for a very long time (and essentially is still today):

  1. Design something in CAD (Side note: Most are not even aware that there are Class A Surfaces and that designing and manufacturing such is an art of its own)
  2. Export as STL → 1st approximation with the precision (chord height) of the respective design tool → 1st lossy operation
  3. Load in slicer → Approximated “chords” are approximated into arcs → 2nd lossy operation
  4. Print design → Arcs are again approximated into discrete X and Y movements → 3rd lossy operation

Now you probably argue, that modern slicers can load STEP / native CAD files directly.
I’m not aware what the slicer’s are actually doing under the hood: Do they really derive the arc from the CAD data or are they just following their regular faceting approach and then “arcify” it.
But fine, you might save one approximation. It does not make it much better.

Given 3D printing’s heritage to CNC, the process in both worlds are very much the same, even with today’s highly complex multi-axis CNCs. The only difference really is that the tool is not called slicer but CAM.

I believe that arcs have only been invented in CNC because it is a major pain in the back to code an arc manually out of normal Gcodes. For a long time and even today, manually programming a CNC is quite common.

The future

If it makes sense to break the concept of slicer and printer firmware, I do not know. Essentially, you would only move the slicer’s intelligence into the printer’s firmware, but you would still need some ways to control the process as the printer can hardly guess what you want.

Maybe there will be AI support. You only throw the model at it and it will automagically turn it into the best possible printed object.

Maybe there will be non-planar printing, which surely would be a big step forward. This concept would also have to be supported by appropriate software and hardware. Both would be a magnitude more complex compared to what we know today.

2 Likes