No sorry. It’s my pleasure dealing with questions (and enigmas) like these.
Indeed now the model is far more complex. Actually somewhat an overkill for an apprentice. I can understand you got stuck, it really is a mindbender, even for an experienced user .
But first: the rule in Hierarchical linking is simple:
one parent can have many children,
but a child can have only one parent.
In Test Animation 011.3dm (568.2 KB) the technique developed in the previous model is taken a bit further:
- 2 diagonal curves are introduced to be use as ‘guides’, since the ‘Spicchio’ should move centripetal.
- A kind of proxy (curve) is used to ‘drive’ the mechanism. Hence CENTRALE A (made telescope child of ‘driver’) is set free to move down and inwards.
Both ‘Spicchio 1’ and ‘Spicchio 2’ are no longer attached to the World (the previous Pivot constraints “Keep pivot location, orientation and scaling”). They are now attached to one of the diagonal curves by means of some auxiliary point-children.
Two are needed to keep ‘Spicchio 1’ horizontal (try deleting point-object ‘constr 1.2’ and see what happens). Only one can suffice for ‘Spicchio 2’ since the system is stable thanks to the previous two.
Nice, but… this techniques doesn’t allow to fulfill your needs (folding up completely). CENTRALE A should go up again but then Bongo has no means to force the ‘Spicchio’ to continue their way inwards. They would simply go back.
Time to change strategy: a different driver: ‘Ala’ is the only element in the system that makes a continuous movement – rotate 180°. But ‘Ala’ not only rotates but it also moves in horizontally! This asks for advanced IK-insight.
After struggling with your model for a while (the horrifying “Bongo: constraint goal not reached” notification) I noticed some miniscule deviations in the position of the solids – probably the side effect of copying.
*So I rebuild the model Test Animation 100.3dm (410.3 KB) – just to make sure.
I also rescaled the model (factor 0.1) to feel more comfortable and also to make the pivots and specifically the IK-decoration more visible.*
In Test Animation 101.3dm (437.4 KB) ‘Wing 1’ (the former ‘Ala 1’) is given keyframes to rotate and it is made telescopic according to the X and Y axis. Hence it will rotate but is free to move around in a Horizontal plane (a “Universal” joint must be used in order to have multiple relaxation).Wow!
An IK element that e.g. is a Telescope cannot be moved via keyframes but it can be rotated or scaled. A hinge on the other hand can only be moved or scaled via keyframes but not rotated. Etc…
‘Part 2’ again is kept in position by two auxiliary point-children constrained to the diagonal curve.
Building out the entire structure in this way, in one long chain, would end up in a cyclical system, since ‘Part 1’ (or a child of it) will be constraint to ‘Wing 1’ (or a child of it). Hence IK-calculation would become recursive! This tought led me to Test Animation 102.3dm (437.6 KB)
Now ‘Part 1’ is made head of the chain. Thus the end of the chain can be constrained to the diagonal curve (which is not part of the IK-chain).
This is another advanced IK technique (I didn’t even mention in my tutorial http://bongo.rhino3d.com/video/whys-of-ik.) : the driver of an IK chain isn’t necessary on the top of the chain. Also an element further down the hierarchy can drive the motion.
The pivot of ‘Part 1’ is rotate 45°. Hence it can be kept on track by making it a simple Telescope.
Don’t get confused. Higher up in the hierarchy (above the driver) “Constraints” can NOT be used but the “Joints” do work perfectly.
There is no longer need for ‘Wing 1’ to be a “Joint”. It executes its Rotation according to its parent ‘Part 1’ and moves along with it. Since ‘Part 1’ remains horizontal that’s just fine.
Finally in Test Animation 103.3dm (463.2 KB) the entire structure is fully completed in one long chain. At the end of the chain a kind of proxy ‘Part’ is formed and constrained to the diagonal curve ‘guide 1’, nicely outside the chain itself.
A lot to handle! Enjoy