Thank you Franck for this detailed and very interesting answer! It's worth +10 to me!
Yes, I'm reformulating, you mention 2 methods:
Method 1: A global skeleton
In this method, the mechanism is built from a single skeleton that is contained within a part. Then, the parts of the mechanism are built from the skeleton. Here, I am missing a little bit of elements to fully understand this method. Hence my question at the end of this post.
Method 2: Basic method without skeleton
In this method, the mechanism is built by an assembly of parts and the parts are constrained together from elements that belong to the volume.
For information, however, it seems to me that there is a third method which is a kind of mix between the two methods, namely:
Method 3: One skeleton per room
In this method, the mechanism is built from parts that each contain a skeleton (which is materialized by a geometric set that contains the wireframes). The parts of the assembly are constrained at the level of the different skeletons. We then obtain that a wired and constrained assembly. The last step is then to add volumes.
Conclusions/questions
For the moment, compared to what I have already done (using method 3), I will go for solution 2 that you told me, namely;
1) Create a "component"
2) Darken the "component"
3) Add the 3D landmarks by instantiating optimized copies based on the skeletons of my different parts.
If you have these axis systems, the simple + is to constrain the 3D marker parts. Quote Franck
--> here, I don't understand why we don't use the optimized copies that we took a long time to define properly.
For method 1, for my information, how are the constraints between the wireframe elements (plane, line, ...) constructed?
Thank you for your ideas and sharing on this discussion, which was very constructive for me.