I also noticed this problem while editing a .dxf produced by Fusion 360. It appears that LC code identifies the presence of extrusion data and calculates the proper rotation matrix to transform the entity from the Object Coordinate System to the World Coordinate System. It applies the rotation to the center point of the entity, but not to the other parameters required to do a correct rotation of the entity onto the 2D plane.
The OCS-WCS rotational transformation in 3 dimensions converts circles/arcs into elliptical shapes. The transformation is required for several kinds of entities and fixing this problem will require a non trivial amount of changes (I think).
I wonder if this is really a Priority 2 level problem? The problem has been around since the beginning of LQ and even QCad. I believe the extrusion feature of .dxf has been around at least since R12.
Last edit: kenr 2019-02-25
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I also noticed this problem while editing a .dxf produced by Fusion 360. It appears that LC code identifies the presence of extrusion data and calculates the proper rotation matrix to transform the entity from the Object Coordinate System to the World Coordinate System. It applies the rotation to the center point of the entity, but not to the other parameters required to do a correct rotation of the entity onto the 2D plane.
The OCS-WCS rotational transformation in 3 dimensions converts circles/arcs into elliptical shapes. The transformation is required for several kinds of entities and fixing this problem will require a non trivial amount of changes (I think).
I wonder if this is really a Priority 2 level problem? The problem has been around since the beginning of LQ and even QCad. I believe the extrusion feature of .dxf has been around at least since R12.
Last edit: kenr 2019-02-25
I would like to work on this problem. I'm new to LC, Git but not to software development. I would like to discuss this with anyone with an opinion.
continued on https://github.com/LibreCAD/LibreCAD/issues/1237