If the Pen Tool is in Bezier mode, how do I reset it to draw only a connected series of straight lines between the nodes - or should I be using a different tool for this?
You can draw curves or straight lines with different mouse button techniques.
[click+drag] places a smooth node and shows a tangent curve. Releasing the mouse button fixes the tangent in place and shows a curve to the next node.
[click] places a cusp node without a tangent and shows a straight line to the next node.
There is an option for this in the toolbar which needs to be enabled:
Beginners' Questions Diable Bezier
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If the Pen Tool is in Bezier mode, how do I reset it to draw only a connected series of straight lines between the nodes - or should I be using a different tool for this?
You can draw curves or straight lines with different mouse button techniques.
[click+drag] places a smooth node and shows a tangent curve. Releasing the mouse button fixes the tangent in place and shows a curve to the next node.
[click] places a cusp node without a tangent and shows a straight line to the next node.
There is an option for this in the toolbar which needs to be enabled: