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The examples proposed were made with the LinkBranch version 2023.811.0 of Realthunder :

PartDesign PartDesign

PartDesign : Mechanics' favorite WB.

Assembly 3 : my favorite assembly WB.


0- Project sources and objectives

This example is an attempt at top-down design using one or more master sketches as well as the Assembly 3 WB.

The parts are deliberately simplified since this is only a proof of concept exercise. I also haven't shown the locking system.

I used the images and dimensions borrowed from the post https://forum.freecad.org/viewtopic.php?t=78962 from @ppemawm, whom I humbly thank for sharing all his magnificent articles.


However, since the goal is to compare top-down design possibilities between Assembly4 (work by @ppemawm) and Assembly3, I advise you to only read the details of the cited article after you have grasped the Assembly3 point of view.

I therefore defined a very simplified draft of the specifications in order to place it in a design context (school-type learning!). This example of specifications therefore provides:


- the dimensions of the half partition of the fuselage on which the components of the mechanism will be attached,

- the size of the unfolded mechanism,

- the dimensions of the wheel,

- the constraint that the folded mechanism must respect,

- a first study defines the skeleton of the mechanism on a master sketch. All dimensions are named
  to allow reuse of them by expressions.

Click on a picture to enlarge it