What is the most efficient way to align imported geometry to the assembly origin?

joseph_brown170

Hi!  I am a Solidworks user learning how to use Onshape.  I have a frame I am building out of 80/20 bars that I am using imported geometry for.  This frame will serve as the boundaries for the rest of the components I mount to it, so I'd like to be able to center the entire thing around the origin, so that the origin is at the center of the frame (floating in space). My main reason for doing this, is that I would like to have coordinate data for some of the moving pieces that I will be mounting on this in reference to a desired point, and not just a random location.  Since I did not model these in a Part Studio, there is currently no origin reference for the individual parts.  If I were in Solidworks, I would just take a central plane from 3 of the beams (Top, Front, and Right), and mate them to the default planes of the top level assembly.  I know that I can't do that here in Onshape, but I am struggling to figure out the best way to do this without adding a sketch in one of the individual part files that calls out where I want the origin to be, and then adding a mate connector there.  This method does not feel very "top-down" to me.  At my last company, it was standard to have every assembly and sub-assembly properly centered around the origin for symmetry if possible.

I have been learning about how to fix geometry from some of the other comment threads and I feel like that may be useful here.  I think my unique challenge is that I have each of these beam files in individual part studios (since they are imported), and am unable to do grouping between them.  

Here is a link to my file: Frame Test

Thanks!

S1mon

There’s a Frame feature with 8020 profiles, so you could easily build this up natively in Onshape.  

eric_pesty

My first thought is that in a case like this, you could literally re-create this frame "natively" in Onshape in a few minutes...



Forgot to create the 5mm offset...



However I am assuming you are looking for a more "general" workflow that you could apply to other cases...
Since it's an import and not "parametric" anyway, I would just create a single reference mate connector in the assembly and placing it at the center using offsets:



It also looks like you made your life a lot harder than necessary with all these mates (and if you ever cause references to get lost it will be way harder to fix). It takes a bit of practice but I have found when working with 80/20 that just mating from the centers with offsets is a lot simpler (once you get used to offseting/rotating mates, which does take some practice to get comfortable with...). Same with your "frame side" subassembly, you actually had 0.52mm error in one of your mate connectors causing things to be mis-aligned.

Here's the "fixed" assembly:





See edited copy of your document: https://cad.onshape.com/documents/dd0c92f0e7f31717453bd211/w/2a95f422b06018c02bd1ba4d/e/3aa3a54ec946c6322461fe9f

I have also found that when it comes to brackets having a few mate connectors defined in the parts really helps speed things up. See my post about this here: https://forum.onshape.com/discussion/comment/87424#Comment_87424

Happy learning, hope that helps!

S1mon

There’s a Frame feature with 8020 profiles, so you could easily build this up natively in Onshape.  

eric_pesty

My first thought is that in a case like this, you could literally re-create this frame "natively" in Onshape in a few minutes...



Forgot to create the 5mm offset...



However I am assuming you are looking for a more "general" workflow that you could apply to other cases...
Since it's an import and not "parametric" anyway, I would just create a single reference mate connector in the assembly and placing it at the center using offsets:



It also looks like you made your life a lot harder than necessary with all these mates (and if you ever cause references to get lost it will be way harder to fix). It takes a bit of practice but I have found when working with 80/20 that just mating from the centers with offsets is a lot simpler (once you get used to offseting/rotating mates, which does take some practice to get comfortable with...). Same with your "frame side" subassembly, you actually had 0.52mm error in one of your mate connectors causing things to be mis-aligned.

Here's the "fixed" assembly:





See edited copy of your document: https://cad.onshape.com/documents/dd0c92f0e7f31717453bd211/w/2a95f422b06018c02bd1ba4d/e/3aa3a54ec946c6322461fe9f

I have also found that when it comes to brackets having a few mate connectors defined in the parts really helps speed things up. See my post about this here: https://forum.onshape.com/discussion/comment/87424#Comment_87424

Happy learning, hope that helps!

joseph_brown170

Thanks so much for this!  I am still becoming familiar with the built-in capabilities of Onshape, but this is great to know.  I think I'll just rebuild it using the 8020 frame tool and learn!