The âissueâ is the due to the fact that result of the constraint of the hydraulic cylinder depends on the result of the constraint of the âfootâ following its Path. The order in which both chains - the leg itself and the hydraulic cylinder - are calculated is random. In your model the legs should be calculate first and then the hydraulic cylinder. Unfortunately Bongo does not allow the user to determine in which order chains have to be solved.
Reversing the chain of the hydraulic cylinder solves the issue. Hence it can be included in the basic chain of the leg. Having multiple constraints in one chain is no problem for the IK solver. Thatâs also the reason why the hydraulic cylinders in the arm of your machinery do not have the âissueâ. All constraints are part of the one chain that begins with Object 1.
In Try 001.3dm (4.2 MB) I transformed one hydraulic cylinder (coloured golden).
2 Auxiliary point had to be added. I assume you can do the others cylinders yourself.
BTW, Interesting model. The fancy walking makes the apparatus look very cute.
If youâll allow me, some commentsâŚ
Object 12 has a âemptyâ Simple Constraint installed. Unharmful but unnecessary. For Objects 7, 113, 133 and 127 the IK âJoint and constraintâ is used. âJointâ suffices.
Object 153 also has an unnecessary Simple Constraint, probably intended to control the telescopic arm. I took the liberty of adding 2 simple Position-keyframes to make the neck extend.
I was being lazy and directly uploaded the entire model. Iâm very grateful that you actually took some time and looked into the model.
For object 12 & 153, yeah I was using simple constraint âto pathâ to make them move. After that I decided to make some keyframes with transforms instead. Then forgot to remove the simple constraints, haha.
For the 4 connections at legs, that I applied âJoint & constraintâ, they were simply joints before. Afterward I found an IK chain with 3 elements will bend into undesired shape when they are following the âstepping motionâ. Thus, I banned the rotation of the middle one.
OK Danny, now I see⌠indeed yes a chain with 2 hinges midways is ambiguous.
But, in order to get rid of the Rotation, you can simply release Objects 113, 119, 127 and 133 (the knee elements) from their Hinge properties, hence from all IK properties.
A uncomplicated, straight forward, âchildâ can be part of an IK chain, as good as Hinges and Telescopes.