Confusion about mates, groups and assemblies

ron_moreland

I have an assembly, call it ASSEMBLY1. I want to it attach to a revolute mate in another assembly, Call it ASSEMBLY_MAIN. I group the parts together in ASSEMBLY1 and create a mate at the pivot point. I insert ASSEMBLY1 into ASSEMBLY_MAIN and create a revolute mate with pivots. When I run the animation, ASSEMBLY1's group doesn't rotate, only the element the owns the pivot rotates. It seems that the solver doesn't respect groups. Is this correct? do I need to use fasten mates for each part in ASSEMBLY1, or import it as a rigid body?  

nick_papageorge_dayjob

You def need the mate to the origin.

But also I believe your issue is which animation button you are pressing. If you go inside a mate (as if to edit it) and press the play button there, it is only solving that individual mate, and only one component will rotate.

If you want to solve everything, you need to use the animate in this screenshot, that shows up when you right click on a mate.

eric_pesty

In Assembly1 you have to connect one of the parts in the group to the assembly mate for this to work.
Or mate one of Assembly1's parts directly in the upper level

ron_moreland

Here is what heirarchy looks like:



Do you mean I need another mate on Part10,11,or 12? 

eric_pesty

ron_moreland said:

Here is what heirarchy looks like:



Do you mean I need another mate on Part10,11,or 12? 

Any one of them... The "triad" icon means they are not constrained.
You can either mate one of them to "Mate connector 1" here, or you can mate it in the higher level (if it makes sense)...

ron_moreland

So even though they are grouped, they are unconstrained

eric_pesty

ron_moreland said:

So even though they are grouped, they are unconstrained

The group mate only constrains them to each other so they move together as one block but you still need to constrain one of them (any one) to something fixed for them to be fully constrained.

You can "fix" one of them however the fix is "local" (i.e. not propagated to higher levels).  

ron_moreland

I put together a test example:
https://cad.onshape.com/documents/8524d969368ead61d2a9652e/w/e8fc2d70d9b7a964aa294dd3/e/d80edd3fa14bdf6df56186e2
I have a simple arm. If you open the revolute mate and push play, only the base element rotates. If you enter values into min and max, the whole group responds.

By the way, thanks for responding .

nick_papageorge_dayjob

As Eric mentioned, one component needs to be mated to the origin (if there is a group). Otherwise everything floats in space, which is what is happening on your example doc. Do that and you should be good.

nick_papageorge_dayjob

You def need the mate to the origin.

But also I believe your issue is which animation button you are pressing. If you go inside a mate (as if to edit it) and press the play button there, it is only solving that individual mate, and only one component will rotate.

If you want to solve everything, you need to use the animate in this screenshot, that shows up when you right click on a mate.

ron_moreland

What do you mean "mated to the origin"? I tried creating a mate connection in Parts Studio, setting the origin to the "origin" dot at the top of the Features list and setting owner to one of the parts in the group. This changed nothing. Sorry for being a bit dense about this.

nick_papageorge_dayjob

Look at this change to your document. Do that in every assembly you ever make going forward and you won't have any issue. Step 1 make a mate connector in the asm at the origin. Step 2 mate the first part to that with a fixed mate. Then proceed as before. Do the same in other subasm's. Then in a top level asm, you can use the MC of each sub to locate the subs.

Link:

https://cad.onshape.com/documents/c44cec8a11af3e22796275fb/v/f158999d3c7ee74b645df110/e/9405d304a1a08a20583bc0f7

ron_moreland

Yep. Wrong animate button! Thanks for setting me straight!