Extrude + Merge error?

tom_auger

Hi folks! I can't for the life of me figure out why this simple operation is causing an error, nor how to go about addressing it (I wish error messages were more helpful in OnShape).

Here are some concentric circles drawn in a sketch on the face of an existing extruded shape. When I extrude them and merge them with that shape I get an error, but only when both of the exterior circle faces are added to the extrusion operation.

Link to the doc is here if anyone has the time to take a peek.

https://cad.onshape.com/documents/a4fffc5d4661140d07d058cf/w/5e47121190aba3b18112f40c/e/5bd89b5b46314bcf9f668a4d

Here's a screenshot - have you encountered anything similar and what did you do to resolve it?

tom_auger

Problem solved: I've seen it before where certain operations in OnShape fail when things are perfectly aligned. In this case the second concentric circle (from the outside) was EXACTLY the same height as the height of the shape it was extruding from, probably causing some kind of division by zero situation. By slightly enlarging that circle (from 40mm to 40.5mm) the extrusion + merge works perfectly.

Hope this helps someone else who stumbles across this situation! I'll try to remember it again in the future.

Keep OnShapin'!

tom_auger

Problem solved: I've seen it before where certain operations in OnShape fail when things are perfectly aligned. In this case the second concentric circle (from the outside) was EXACTLY the same height as the height of the shape it was extruding from, probably causing some kind of division by zero situation. By slightly enlarging that circle (from 40mm to 40.5mm) the extrusion + merge works perfectly.

Hope this helps someone else who stumbles across this situation! I'll try to remember it again in the future.

Keep OnShapin'!

bradley_sauln

Glad to see you resolved this yourself. You are pretty on point with what is going on. What happened was you created what is called zero-thickness geometry or non-manifold geometry.

If you find yourself consistently hitting this then let's have a chat! Usually making slight tweaks to how you approach designing can help to avoid this altogether

tom_auger

bradley_sauln said:

If you find yourself consistently hitting this then let's have a chat! Usually making slight tweaks to how you approach designing can help to avoid this altogether

These days I'm always up for a chat! I have so much to learn still but OnShape has opened up a whole new world to me and I'm constantly stoked to open it up and create parts to solve everyday problems.