I had similar problems when upgrading to a newer Windows version some weeks ago. I turned out to be not having the splash screen enabled. I installed (unzipped) an older version I knew was working OK, enabled the splash screen in preferences. Newer version have run OK ever since. Some rescent versio...

If you are importing an stl into Blender you have to scale by 0.001.

A unit in Blender is 1m. Prusa Slicer see a unit as 1mm.

So, it depends on the software you are importing into.

Here is a simple 8mm 3D printer rod with 7 starts ISO trapezoid thread.

Cut 1 thread using subtractive pipe.
Polar array the rest.
Grove to chamfer the ends.

While FC crunches the number, go make yourself a cup of tea.

Thanks drmarco,

That's a different method. Got rid of the Datum Plane.

None of my Datum Points in my original reply were attach to the model. I avoid topo issues like the plague.

Reynard

Hi drmarco,

I created the Datum Points onto the XY-Plane. That way the local and world co-ordinates matched up.

Can't work out how to get the Sketcher to snap to the Datum Points to draw a triangle to pocket. Seems not possible.

Reynard

Create 3 Datum Points at the co-ordinates you need.
Create a Datum Plate onto these 3 Datum Points.
Sketch a shape (Rectangle maybe) that encompasses the three Datum Points.
Pocket the shape in the correct direction. Probably reversed.

Since we are on the subject of Plane direction, something that confuses me is that if I create a datum plane on the XZ world plane I would expect the datum plane normal (Z) to follow the remaining world (Y) but it does the opposite. There is probably a very good reason for this, like "it's too ...

Ahhhh! That Hole. I was thinking pocket.

Yes, a reverse check box would be nice to have.

As QUEEN would say, "Its a kind of magic".

Both Pocket and Datum Plane dialog boxes have a reverse check box in them. Experiment with them.

Reynard

Yes datum planes do seem like trial and error to see which way they move, but you work something out eventually.

I have been struggling to get the file size below the 1Mb mark. Using compression level 9 seemed to do it.

File attached.