Posted by Jaycad on Jun 11, 2022; 8:10pm
URL: https://forum.librecad.org/Using-Librecad-to-analize-bike-geometry-tp5719645p5721785.html

A late reply on this but one way of getting an image taken parallel to the plane of the bike frame is to place some sort of coarse  "grid" object against the bike (something with horizontal and vertical lines) and rectifying the image, either using the rear screen guidelines of a digital camera or via software.

Hugin panoramic stitching software (free!) can rectify an image on parallel lines.  There is a tutorial on the Hugin website on how to do this.  It can also be used to rectify an image of a building facade, which can be drawn over in Librecad to create an elevation drawing.

One thing to watch with drawing over rectfied images - objects that are not on the plane of rectification will be either at too small or too large a scale, and not in the correct position.  Therefore care has to be taken with this approach.