[BUG] Difficulty Exporting Chains

[willpuckett]

Describe the Bug
I am experiencing difficulty exporting chains.

To Reproduce
Using a rectangular plane with two circles in it—

I create an outside profile cut operation for the plane, and an inside profile cut operation for the circles.

Running Calculate Path & Export Gcode on the operations individually outputs the tool paths and gcode file, but when I group them together as a chain, I get AttributeError: Curve object has no attribute 'vertices'.

I have noticed that when outputting an operation individually, the created path is a mesh:

But when I create an additional operation's path, the first path is changed into a curve:

I tried converting the curve path to a mesh and using the Export Chain Gcode button and the command executes without error, but when I cut it the travel moves didn't lift correctly and the workpiece was gouged in several places.

Expected Behavior
Pressing Calculate Chain Paths & Export Gcode will calculate all paths and export them without error, regardless of what is selected.

System Information:

• OS: MacOS Sequoia
• Blender Version: 4.3.2
• Addon Version: 1.0.61

Error Message:
AttributeError: Curve object has no attribute 'vertices'

Additional context

[willpuckett]

I'm also sometimes getting a remove doubles error when processing a cam operation, as in #271.

[robinhyman]

I am also getting this exact issue running extension version 1.0.65 in Blender 4.2.2 LTS on Windows