We use the triangles of the mesh of the objects. Then calculate the lines where triangles intersect with a plane. Then create new 2D meshes based on the points on the end of the lines.
Sorry for the late respond, and thanks for the love. :D
Oh ok. Idk how one would check if the triangles of the mesh of objects intersect with planes (Maybe on collision check distance of each triangle from the plane? Idk). But that simply means I am yet to study and research more into things before I can try my hand at it and comprehend that haha. Thanks a lot. Ill treasure your comment till I learn things and try replicating your method (That is if you dont mind). Sounds interesting btw n love you for sharing the info.