how to assemble joints for a bike chain
In theory (and ONLY in theory) this could be done with a complex set of joints- for each end of each chain link, and one for the crank- and contact sets. In practice, it is certainly far beyond the ability of Fusion’s contact sets to animate something like this. Contact sets work well for very simple interactions, such as checking for interference in motion, but more complex situations involve too much computation.
Here's a tip on the use of motion and contact sets. https://forums.autodesk.com/t5/design-differently/creating-contact-sets-and-motion-links-in-fusion-3...
Mostly Mac- currently M1 MacBook Pro
To be completely honest here, I would not attempt this. The mechanism involved requires an extremely large number of joints, and will likely not perform well for you, and you will get very frustrated. And, that's probably true for any CAD product, not just Fusion. I once tried to model just a bike chain. I eventually shortened it up quite a bit from its real length, just to see if I could get it to work. I got it all assembled (using just revolute joints). But, it did not behave very well during motion. Without getting into too many details, the problem, from a solver point of view, is that it defines a closed cycle of joints, (imagine not a 4-bar linkage, but a 114-bar linkage). This is a challenge for any constraint solver.
And, that's just the chain. Then, trying to get the chain to work with the gears is another problem. @Oceanconcepts mentions contact sets. I would have to agree with him, and gently steer you away from contact sets for this usage. Contact sets work pretty well for a small number of components with fairly simple geometry. But trying to use it to model a bike chain assembly will not make Fusion or you happy. You would have to add every link in the chain, plus the two gears to the contact set.
Then, if you wanted to try to model the derailleur... It makes my head hurt just thinking about it.
If I were designing a bicycle, I would just use Motion Link to relate the front and rear gears together, and either model the chain in one position (if I was really ambitious), or just skip the chain entirely. With Motion Link, you could even simulate gear changes. Just change the ratio in the Motion Link. With the Fusion API, I'm willing to bet that you could produce some UI around gear changes.
While this is probably not the answer you were hoping for, I hope that it helps in your understanding.
Jeff Strater (Fusion development)
Jeff Strater
Engineering Director
In short, as other have already mentioned I would also NOT attempt to do this with Fusion 360.
Joints and contact sets in Fusion 360 are a manesn to simulate motion and to highlight postential problems and limitaions of a design.
For example if you design a rear derailleur, Fusion is an excellent tool to simulate if your shifting mechanism has enbough range to cover all gears.
As a pure animation tool Fusion 360 has it's limits and is really not the appropriate tool. 3Dmax for example would be better suited for this. I personally woud use Blender for this.
