Mates for a L-shape path

johannes_becker

Is there a way to to restrict the movement of parts in an assembly such that one part can move only along a L shape path? It is for a part that drops in from above and then slides horizontally. It would be like a slider mate vertically and at the end of the allowed path a slider mate horizontally.

Any hint will be appreciated

Johannes

EvanReese

You can kind of cheat it using some dummy parts and surfaces and a tangent mate. Here's a super quick example. @john_mcclary
is the master of this technique though, so he probably has better input. I mean, he animated solving a whole rubiks cube in Onshape which still blows my mind.

john_mcclary

@Evan_Reese
yea, that's pretty much how I would have done it

Further Suggestion:
If you have a lot of places where that path is needed, then you could make a configurable assembly that has the path and arrow, insert that assembly in every place you need to mate, and change its configuration to drive the path and shape. That way you can have a ready to go "L-Mate" that can be re-used while only drawing it once. At the same time the configurations set the 'limits". Then add a couple of mate connectors within it and it should be a rather decent work around. rather than matting a bunch of stuff in the main assembly on the fly.

matthew_stacy

@johannes_w,

I am many things, but fast ain't one of them.  @e@Evan_Reese and and @j@john_mcclary beat me to the punch, but for whatever it's worth here's another serving of the same basic flavor.  Onshape has a useful tech tip video demonstrating a related application of the tangent mate.

Note, that one requirement to radius the corner of the "L".  Make that radius as small as you want, but R>0.  The only way that I could get the tangent mate to accept the entire face of the "L" was to construct a dummy PART.  Kudos to John for making that work with a SURFACE.  I'm still not sure how he did that.

I chose to use a ball (sketch & part) and a "Ramp" part:

• Ramp is fixed
• ball sketch grouped with Ball part
  
• ball sketch mated planar to origin (orientation of that origin mate connector can be persnickety)
  
• vertex of ball sketch mated tangent to face of Ramp part (dummy)
  

Hide, but don't suppress, the dummy.  Note that you can mate the surface of the ball part tangent to the ramp (B1 branch, V2), but the geometry calculations must be more complex because the movement is not as stable when you drag the ball around the corner.  I suspect the singularity of a sketch vertex is the better choice (Main branch, V1)

johannes_becker

Thanks folks. I will give that a try