Hi Iain, there isn't any automatic way right now, but a few different manual methods are possible. Pilou shows one way of using booleans.

Another method is to build a set of planes that intersect your object, and then run the Construct / Curve / Isect command. That command calculates the curves of intersection between objects.

Here's an example - I started by drawing a line to the side of the model to cut, and then used Construct Extrude to punch it up into a plane:




Next I made a bunch of copies of the plane along one direction using Transform / Array / Dir:



Then select everything and run Construct / Curve / Isect - this will generate the curves where the planes intersect the object, I think these are the curves you're looking for. Here I used Select / Invert to select and delete the original object and planes:



I do want to add a more bundled up cross-sectioning tool in a future version but for now this should get the job done.

Hope this helps! Let me know if you get stuck or have any questions on any of these steps.

- Michael