How do you position an imported component using parametric modeling?

[Anonymous]

I am designing a router table that has casters, which I have imported from McMaster Carr.  I am using the parametric modeling table because I am still tweaking the dimensions prior to assembly.  However, if I change a parameter, the position of the casters does not update with the rest of the model.  For example, if I add 2 inches to the length of the leg, I want the caster to drop 2 inches.  I have tried using a rigid joint to join the caster and leg, but that didn't work.  Is there a way to fix an imported component relative to another component so that when the dimensions change, the postion of the improted component update properly?

Thanks for your help

[jhackney1972]

There should be no issue with your design.  You want to make sure your have the correct component grounded so everything can update correctly.  Take a look at my Screencast where I have a simple assembly with a McMaster-Carr swivel caster in the end of the leg.  I have a length parameter on the leg component.  If you need additional help, give the forum a link to your assembly so we can take a look at your actual design.

[Anonymous]

Thank you for the quick reply.  I had not grounded any components, but unfortunately this didn't seem to solve my problem.  I tried grounding the bottom frame, then tried the top.  Each different time I made rigid joints between each part from the grounded part to the caster (e.g Top -->Leg-->Bottom Frame--Caster).  Every way I tried it, the casters stayed still while the rest of the table changed size.  The components are nested together.  I also tried joining individual instances of a caster, pulling the casters out of the nested component.  I'm sure its something simple I'm missing.  Thanks again.

Here is a link to my project: https://a360.co/2VJgIYG

[jhackney1972]

What I found was that one of the legs was lacking the parameter that governed its length.  Also the Rigid joint between the casters and the frame not to a member that was changing position.  I removed all these joints and replaced one.  I am not sure it the location is exactly correct but I just wanted to prove a point.  Your ground component is just fine, the table top.  I have attached my modification assembly with a different name to this post so you will not confuse it with yours.  I only did one caster as I am not the designer and I want you to place them as you desire.  Just select a joint origin point that changes with the table height.  The one caster I changed updates with the table height.  Why did you create a sub-assembly with just the casters, nothing wrong with it but...

[Anonymous]

So I got it to work but I'm not sure what went wrong.  How I fixed it was deleting the casters, re-importing them one at a time, then creating the joint, and it worked as it should. The only difference in process I can remember is the way I copied the casters.  The first time, I inserted one, then mirrored it twice to get 4 copies.  The second time, I inserted 4 individual instances of the casters.  I'm guessing the mirroring was the problem.

Either way, your advice led me down the right path.  Thank you again.

[Anonymous]

I nested the components so I can easily hide them with one click while tinkering with the other parts.

[jhackney1972 · Accepted solution]

Next time, group your components in a Selection Set instead of a sub-assembly.  You can show, hide or isolate selection sets very easy.  Please mark your forum post as "solved" if you have your answer.  This is a good habit to get into when a forum question is finished.  It helps others find your solution and it removes it from searches.