Demkamen
curious, I provided the "Set Origin" action to be able to change the center of the polygon (like a pivot point), most people would never use it though. What it does is just offsetting the position of the vertices and compensating by setting x and y of the object so the polygon doesn't seem to move. So it shouldn't change anything in regard to the chipmunk behaviour.
Or maybe I misunderstand what you mean by "to add origin point", if you mean that you have to setup the vertices, then yes, since the physics engine need the polygon to work.
As far as managing points for big levels, well... C2 doesn't have any SDK to design any kind of advanced editor,... well, any kind of editor really, I remember being desesperate about the look of the plugin in the editor, I mean... I couldn't find any good way to display it. It would have been nice to at least be able to leverage the collision polygon tool of the image editor, but alas...
I guess I could have put a property in the property editor where you could have listed vertices... But it seemed at the time, and still today, kind of useless...
What I would advise is to look for some tool (or maybe even make one in C2) where you can create polygons and export a json, and then load it and rebuild the polygon by looping through the points defined in the json...
(hm... I just realized that there's two AsJSON expression... just try one that work :D... not sure I'll ever really update that plugin... if I do, one day, I might actually implement what I mentionned earlier, the property with the list of vertices... but meh... )