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Mirror Extrude Should Always Have a Symmetric Result

paul_bunnellpaul_bunnell Member Posts: 26 EDU
edited December 2020 in Product Feedback
It seems to me that mirroring anything should produce a symmetric outcome, but that is often not the case when mirroring a feature.  The short version is that I have an extrude with "up to face" as the end condition that removes the the right 1/3, then the mirror is not removing the left 1/3, it is removing the left 2/3 (up to the same face as the original)


The clearance for the right knuckle is an extrude-remove going from the outside inward up to the inner circular face of the right knuckle.  I'll call it Face A. (plus an offset). 

The tab "Is - Before" shows everything up to that point with the mirror suppressed.

The tab "Is - After" enables the mirror.  The reason the middle knuckle is gone is that the mirrored cut isn't removing the left 1/3, it is removing the left 2/3 because it is going up to Face A.

The tab "Ought" changes the extrude from "remove" to "new" and creates a temporary cylinder.  Mirror is changed from mirror feature to mirror part and works as one would expect.  Then the boolean subtracts the two temporary cylinders to create the cuts.

Obviously the "ought" tab is a viable work-around, but In my mind, the outcome of a mirror should always be symmetric. 

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Comments

  • lougallolougallo Member, Moderator, Onshape Employees, Developers, csevp Posts: 2,005
    @paul_bunnell Feature mirror mirrors the feature and its end conditions. In some cases things like planes and other sub features including end conditions can alter the result.  Also including things like sketches, today we do not mirror or pattern the external references of sketches so the results can be mixed.
    Lou Gallo / PD/UX - Support - Community / Onshape, Inc.
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