How to setup a freeform trajectory in impress?

Hi,

I would like in LibnreOffice Impress 5.2.3.3 (windows version) move an object (i.e. picture) according to a curve I would specify.
In Animating Objects in Presentation Slides - LibreOffice Help, it says to select the “freeform” trajectory yet I can’t find it, I just see predefined animation such as “S-Curve 1”, “Right”, “Parallelogram”.
I can modify some of the animations but not to the extent where I could create a freeform curve.

Regards
Matt

EDIT: the animation system seems broken in several ways :’(
1/ If you select one trajectory, an arrow picturing trajectory is drawen, then if you select a different one, the previewed trajectory is not updated, you have to change slide and go back to see it updated
2/ if you modify trajectories by double click → moving control points, it is not always saved while changing the bounding box seems ok.

I do see a Freeform Line option in the Custom animation sidebar. See attached image. LibreOffice Impress 5.1 on Fedora 24 (don’t know about LO 5.2 on WIndows).

I can draw a freeform line so the picture follows its path.

Thanks for the great screenshot ! I don’t have a “user paths” section on Ubuntu 16.10, LO 5.2.2.2 it starts straight at Basic :’(

I upgraded my system to Fedora 25 and LO 5.2.3.3. Now I don’t have the same dialog as in LO 5.1, and there is no “User paths” section in my animation pane. Sorry.