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Belt Feature Studio - using two same size cylinders - generates an intersecting path

I was using the Belt feature I found in the public documents.  When I had two different size pulleys it worked OK.  But I needed to make them the same size, and when I did that, the arc at one end, was flipped back over the in and out line ends - and will not generate.  I took a look, and the midVec lenght becomes zero length, and then becomes the segment across from the in to out points - I used the zero case to use the inVec unit vector, and use that with the radius at the center. Then it worked fine, at least in the part studio.

I did find that all the samples in the public document are part studios, no assemblies.  When I used my belt, in the higher assembly - it cannot be created...but the error is basically that and is not actionable.


  • TimRiceTimRice Member, Moderator, Onshape Employees Posts: 312
    @paul_chastell is the creator of the FS and may be able to help. As for your second question, would you mind explaining more or sharing a link to the doc?
    Tim Rice | User Experience | Support 
    Onshape, Inc.
  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 3,930
    Hi @charles_doughty - I've been working with the belt feature recently and I am unable to reproduce your same size issue. The samples in the document also include two cylinders of the same diameter, so if you want to make your doc pubic or raise a ticket and share it with support we can take a look. FeatureScript is for generating part features that is why they only work in Part Studios - create a sketch in your Part Studio to represent the layout of your pulleys, build the belt, then assemble the belt into the assembly.
    Director, Technical Services, EMEAI
  • charles_doughtycharles_doughty Member Posts: 3 PRO
    Hello Neil and Tim.  I shared the document with you, with edit.  I included comments there, similar to the below.
    For others,  whatever I did wrong, the generated sketch for the belt, with just two identical sized pullerys/sprockets one end the arc was around the exterior of the pulley, as expected. The other end, folded the arc back around the inside/interior side of the pulley, and could not generate the extrude...said intersecting path?
    I would have to go back to the original feature - to generate a screen shot.
    not sure how to represent the pulleys in a sketch - the frame sketch has both shaft locations - that what you mean?  Not a clue as to how to assemble the belt from a sketch in an assembly.  I am totally new  user - literally just this month.

  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 3,930
    Hi Charles, I cannot work out why the belt is failing. I tried editing your sketches to tidy them up, making the assumption that the feature prerequisites were not met (cylinders with parallel axes) but that did not help, so I have forwarded it on to the original developer. For a workaround, I created a sketch on Plane2 with 2 circles in your document, constrained them to the sprockets, extruded them as surfaces, then used those to create a belt. To use this belt in the assembly you must manually assemble it and then mate it to your sprockets. 
    Director, Technical Services, EMEAI
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