The black structure and the purple structure are identical but for one thing: where the ‘spline vertex’ and ‘spline tangent’ field fir the relevant vector-list, the purple one points to a reference, and then to a vector-list. I want to do this so that I can attach multiple things to the spline (vector-list) , and more easily swap out which spline they are all stuck to.
Play it and see the stars roll. Now, select ‘roller’, then the black star, grab the green duck and notice how it nicely constrains the motion (thanks to my use of an ‘add’ node in the ‘amount’ field of spline-vertex).
Now try it with the purple structure: click “purple roller”, then the purple star, pull the green duck, and watch synfig freeze for a second or three, then crash.
I followed the steps and yes, it crashes.
Here are steps more clarified,
Open the file
Select the roller group, move the group by dragging the Green Duck/Position Handle (you can notice that it follows the Spline black line
Select the purple roller group, move the group by dragging the it’s Position Handle (Green)
Synfig crashes
This is crashing because, according to my knowledge there is no inverse support for Reference converter.
Here’s what I mean by inverse support is, the ability to get the Amount Parameter by manipulating the Origin in GUI.
As mentioned above you should report this on GitHub.
Thanks for having a look. I agree with Veer’s thoughts, and think that this may be asking a little bit more of some special-case code than originally conceived. I’ve been using this forum to report such things because I’ve been too lazy to figure out how to do it in the proper development workspace, and I plan to work out that procedure soon.