Select the objects you wish to see in a simulated preview. If you want to watch your whole design being simulated, select everything (Ctrl+A) or nothing.

Then run Extensions > Ink/Stitch > Simulate and enjoy.

Simulation Shortcut Keys

Shortcut Keys Effect
play forward
play backward
speed up
slow down
+ one frame forward
- one frame backward
p pause animation
r restart animation
o display needle penetration points
q close

It is also possible to zoom and pan the simulation with the mouse.

Run Simulator Independently

Run the simulator by itself on any supported embroidery file:

PYTHONPATH=/usr/share/inkscape/extensions python -m lib.simulator path/to/myfile.ext