Sketch fails to Extrude, wondering why?

john_lopez363
john_lopez363 Member Posts: 143 ✭✭✭
in Community Support
I have the following sketch...  wondering why it fails to Extrude?

The sketch consists of a block with 8 circles arranged tangent to each other and coincident to a central construction line (inner circle).

How can I resolve this?






Answers

  • Matt_Shields
    Matt_Shields Member, Onshape Employees Posts: 991 PRO
    That extrusion would result in zero-thickness geometry, which is not allowed.  I believe it is called non-manifold geometry.  Try a small gap or a small overlap.

  • john_lopez363
    john_lopez363 Member Posts: 143 ✭✭✭
    @Matt_Shields... Thanks for the reply.  Your suggestion is definitely a work around. 

    At first I thought it might have something to do with the shapes being circles, but no, it does not matter what geometric shape it is.  As long as two shapes intersect at only a single point in their geometries the Extrude will fail.   I tried several other shape combinations and all resulted in the same failure.

    Guessing this is a defect/bug in the software.

    @Onshape... ?



  • _anton
    _anton Member, Onshape Employees Posts: 553 image
    This is a common limitation in CAD. You can't manufacture zero-thickness geometry anyway, so Matt's suggestion is to essentially make the part physically possible.

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