Onshape parts will no longer move in an assembly?

16156Rcubed

I was 98% done with a robot prototype when I lost the ability to move the parts in an assembly to create the final robot design. Everything is fastened mated as far as I can tell. This is my very first Onshape student project.

https://cad.onshape.com/documents/939328a0518b2e25e2f15e00/w/5cc8dcfe4f7869eb5b7f49d5/e/96393f2ca2e9667c36627ba2

john_mcclary

Everything is group or fasten mate.

Those both restrict movement.

If you need things to move, you will need to use less restricting mates, such as revolute.

You will never want to use a group mate with an assembly either. That alone will cause other problems down the line

robert_scott_jr_

You will never want to use a group mate with an assembly either. That alone will cause other problems down the line

So parts that have been conveniently grouped should instead be fastened? When is the group mate intended to be used? - Scotty

john_mcclary

You can use group on everything, but if you select an assembly then it basically freezes that assembly on this level.

So if you update the sub assembly the positions of the parts will not update or worse yet, appear to explode. 

All you need to do is suppress then unsuppress each group mate to fix it. But that step is not a good workflow

The proper way is to mate everything in the subassembly how you want. Then on the higher level assembly, you only attach the sub assembly by the one connection point.

16156Rcubed

Thanks so much! This helps a ton! We're still breaking it but not as often. We're just too new at Onshape. -- 16156 R-cubed FTC

john_mcclary

It's no problem, I was all for group mate at first. It took many hard lessons to get me to really understand when to group and when to avoid it.

Practice, Practice, Practice