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Physical/Collision Stop Faces

Hey,

It would be really nice to be able to limit the movement in an assembly if it was possible to just set stop/collision faces. basically, just select the two surfaces you want the collision to happen between, and click OK. after this the two surfaces wont go through eachother, and instead collide and stop.

Like I have this part now. instead of using the cylindrical mate and trying to figure out the stop limits etc. I just want to set the cylindrical mate. then in another action I want to set a physical stop between surface 1 and surface 2.


Comments

  • Evan_ReeseEvan_Reese Member Posts: 2,064 PRO
    This could be really cool! No idea what kinds of complications I'm not imagining, but I can certainly picture use-cases
    Evan Reese / Principal and Industrial Designer with Ovyl
    Website: ovyl.io
  • glen_dewsburyglen_dewsbury Member Posts: 577 ✭✭✭
    I learned this at a webinar last week. More convoluted than what you/we are asking for but it works.
    Zero minimum sliders with no max.
    https://cad.onshape.com/documents/eeff86f87f2b3be9ae6915b8/w/c75821c5084576f01fba38b9/e/edd881e3560406f61b23bbe3
  • eric_pestyeric_pesty Member Posts: 1,488 PRO
    There are already some IR about physical limits (i.e. collision detection), but that might a good way of implementing this in a more "flexible" way, and most likely with less performance impact. Kind of like the "mate relations" but for limits.

    You can sort of do this right now by using more than one mate although picking the right mate can be tricky to avoid over-defining. Sometimes you need an extra piece of "dummy" geometry to allow this. In your example you would need to insert "something" like a small surface or a sketch or whatever with a revolute mate along the edge of your contact face (or maybe a spherical mate on the center of that face?) and then a parallel mate with a one-sided limit along your "stop" face.
  • Ketil_Volland_WorkKetil_Volland_Work Member Posts: 38 PRO
    This sounds like a good idea and might deserve its own IR.
  • sebastian_glanznersebastian_glanzner Member, Developers Posts: 398 PRO
    I use the "Parallel Mate" between touching faces and set the min and max limits.
  • eric_pestyeric_pesty Member Posts: 1,488 PRO
    I use the "Parallel Mate" between touching faces and set the min and max limits.
    The only downside is that the limits are not "parametric" when doing it that way. One alternative is to use two mates with only one sided limits, this way it will remain correct if the geometry changes.



    It's just when things rotate as well you can't do it one step so that is where you need an intermediate "dummy part". Basically what you would need is a "universal" mate, like a tangent but that lets you set limits for how far away from the surface you can be or a parallel that's also a ball mate. Basically a mate that doesn't actually constrain any degree of freedom totally (just allowing limits), sounds dumb but could be useful sometimes! 

    https://cad.onshape.com/documents/9730f63b6e66517f279fd274/w/91f81bcd98f3e457a36e8a3e/e/553c461c6f293f46d446bd7b
  • wout_theelen541wout_theelen541 Member, csevp Posts: 198 PRO
    I learned this at a webinar last week. More convoluted than what you/we are asking for but it works.
    Zero minimum sliders with no max.
    https://cad.onshape.com/documents/eeff86f87f2b3be9ae6915b8/w/c75821c5084576f01fba38b9/e/edd881e3560406f61b23bbe3
    The link was broken but I figured it out.
    It's a cool workaround though. 

  • brodie_lloydbrodie_lloyd Member Posts: 2
    Hi All,

    I am new to Onshape and loving some of the unique approaches the team has come up with 3D modeling, mates and assemblies. 

    One feature the team NEEDs to include (as a priority) and is the only down side I have seen so far, is the lack of motion 'Collision Detection' based on part surfaces geometry during assembly motion. Currently there is no option with the existing mates constraint system within on shape to restrict part motion based on part surface interaction (without apply known preset limits and angles). Having to manually input these takes away a lot of the design advantages of a motion analysis using a 3D model assembly. 

    If this feature exists, my apologies (please let me know how to do this). BUT if not this should be the OnShape teams' main focus at present and will be an equaliser for many users currently on the fence with competitors like Solid Works and Inventor. 

    I can not see how this would be a difficult inclusion with assemblies as it is a motion check based on the static 'Interference detection' already built in to the software (see links below - I am sure the devil is in the detail however).
    * IMPROVEMENTS TO ONSHAPE - OCTOBER 17TH, 2019 - https://forum.onshape.com/discussion/comment/57182#Comment_57182
    Interference detection - https://cad.onshape.com/help/Content/analysis_tools.htm#Interfer

    Any information regarding this feature development / existence / thoughts from the Onshape team would be greatly appreciated! 

    As always, keep up the great work Onshape team!
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