[2.9.0-pre1] Rotary axis backplot not displaying

Hi all,

Before I take this to github I'd like to investigate with the forum experts whether this is bug, a config issue or myself still being a rookie.

The machine is a fairly standard XYZA. I am unable to have the rotary toolpath displayed correctly inside Linuxcnc. I am attaching the SIM I am testing this with along with the gcode program of a 360deg rotation around the x axis.

Ref to: 
[DISPLAY] 
GEOMETRY = AXYZ 

That is the 'standard' way the preview handles rotations. However there is a, somewhat experimental, addition to version 2.9 that may do what you want.

In the [DISPLAY] section your ini file change this:

GEOMETRY = AXYZ

to this (note the exclamation mark before A)

GEOMETRY = !AXYZ

 

• Experimental: If the exclamation mark (
  Code:

  !
  ) character is included in the GEOMETRY string, display points for A, B, C rotations respect the X, Y, Z offsets set by G5x, G92 codes. Example: Using
  Code:

  GEOMETRY = !CXZ
  for a machine with
  Code:

  [TRAJ]COORDINATES=XZC
  . This provision applies for liveplots only — G-code previews should be done with zero G5x, G92 offsets. This can be facilitated by setting offsets in programs only when task is running as indicated by #<_task> == 1. If nonzero offsets exist at startup due to persistence, offsets should be zeroed and preview reloaded.

linuxcnc.org/docs/2.9/html/config/ini-co...#sub:ini:sec:display

Thanks for the kind help, Aciera. This !AXYZ actually does work however is there a reason why the the toolpath diameter increases by 1km when G54 is set elsewhere than the MCS? Appears to display fine if set on the MCS(0,0,0,0) though.

Fair to assume this is a 2.9.0-pre1 bug or a unimplemented feature perhaps?

Well reading this:

This provision applies for liveplots only — G-code previews should be done with zero G5x, G92 offsets. This can be facilitated by setting offsets in programs only when task is running as indicated by #<_task> == 1. If nonzero offsets exist at startup due to persistence, offsets should be zeroed and preview reloaded.

It seems that the developer is aware of the issue. So I'd say it is a 'known limitation' of the feature.

Fair enough. I'll see if I can find time (I highly doubt) to get inside the code and propose a workaround. More or less 95% of the machining on this machine-tool is carried on the 4axis, and so hope for this to be looked at is high!

Noticed earlier that 2.8.4 displays rotary toolpaths perfectly fine though. That might be the solution, we'll see.

Appreciate the help and input, Aciera ✌. Wish you well and all the best.

Noticed earlier that 2.8.4 displays rotary toolpaths perfectly fine though.

I wasn't aware of that, maybe something changed with the move to python3 / gtk3 but I really don't know.

Aciera wrote:

I wasn't aware of that.

For the record; it neither work in 2.8.4. Same problem, apologies for misleading. I've downgraded a vm today from 2.9 to 2.8 to find out my initial observation/confirmation was based on a 0,0,0 coordinate. Once offsets are applied the validation fails and machining enters a at-your-own-risk state and territory.