Ripples in solid thickened from straight surface

tony_459

I used Fill to create a surface and the surface came out sufficiently straight and clean that I felt comfortable using it.

Yet, when I thickened the surface to generate a solid from it, I got ripples that were no where in the surface. The ripples, in the light gray part:

The surface, with edges highlighted (and dashed, as they go through the solid in this view). Note how straight the red edge is and how straight the thickened solid isn't:

This isn't usable geometry and it's very difficult to clean up. I could spend two hours trying to find some combination of solid operations to undo the ripples that the thicken operation produced.

Can someone explain why the ripples would form to begin with, and how best to go about avoiding them, and if not avoid them  then at least efficiently remove them, without producing messy geometry?

konstantin_shiriazdanov

I find offseting and thickening one of the most capricious operations in any parametric system. Their result highly depends on curvature stability of the reference surface, so it's almost every time a struggle when you dealing with something more complex then primitive surface types. In the high level systems they have rough offset and partial offset tools, but often the only way is to make offset surface from scratch based on the curve cage

NeilCooke

@tony_soares459 seems like you're not having much luck with this model. Share the URL so we can help. The original surface is clearly not as clean as you may think.

tony_459

Thank you both for responding

This particular model is top secret and I'd rather not share the URL here, but the question is general and does not depend on the details of the model except for illustration purposes.

My experience with thickens has been mixed, too, and I suspected I'd run into issues of this sort, so I'll try a different approach---to create solids of this kind by enclosing the volume between custom surfaces, which however slow might be to make, should give me the control I need over the final solid geometry.

I guess I was hoping to hear thickens are OK---hoping because they are very very quick to do---but sometimes control matters more than speed, and that means I need to make the time to more carefully make the pickier geometries.

NeilCooke

Hate to break it to you @tony_soares459 but Public docs are not top secret 

tony_459

You're free to rummage through my models, I'm just not advertising the URL here

steve_shubin

@tony_soares459

If you’re still looking for a solution to your rippled part, here’s a suggestion. Maybe this would be something you’d feel comfortable with doing

It’s understood that you would like to keep others from seeing your design. If you share a stripped down and renamed copy of your project, it’s possible that others wouldn’t be able to determine what it is that you’re trying to make. This could be a way of keeping your project private.

If this sounds plausible, read on.

Make a copy of your document. Regarding this copy — delete every tab except the one part studio that has the part with the ripples. 

In this one part studio remaining, delete all sketches except for those that you used to make the part with the ripples.

And then lastly, change the name of the document to something else.

Then share that stripped down and renamed copy so people can take a look at it.

I know there’s a lot of helpful people in this forum. Who knows — this might lead to eliminating the ripples without compromising the privacy of your project

john_mcclary

It would be quicker to duplicate the part studio then 'move' it to a new document, then share that doc.

steve_shubin

@john_mcclary

Yeah, if he has a lot of tabs, I could definitely see duplicating the Part Studio and moving it to a different document. That’s great advice John.

It would be nice to have that ability to move a tab to a different document via mobile Onshape

In either case, he is still gonna have to strip out sketches he doesn’t want people to see in that rippled part tab, such as sketches used for making other parts

tony_459

I appreciate your desire to help, but I... won't have you do my work.

My question was general in nature and not worth the trouble of duplicating documents or tabs and suppressing features, though I'll keep these suggestions in mind if ever a question warrants them. 

A rippled solid is not the most obvious result of a thicken of an unrippled surface, and I was looking for some thoughts on what might cause them and how to avoid or repair them. General info for a general problem that I've encountered in different contexts before.

I wound up taking the long route to create the solid from surfaces that I created from edges. I ran into other issues there, but nothing I couldn't resolve in the end. (A ripple is effectively a dead end if I can't resolve it.)

Thanks again for the interest in my (unusual) question.

john_mcclary

The unusual nature of the ripple is why we would need to see it, if we try and duplicate a ripple then we would intentionally try and draw a ripple. there are probably 10 different ways to draw a ripple, so it would be hard to say what went wrong with your document. If it is a bug or something you may be doing wrong.   I understand you don't want to share your model. So then share it with the onshape staff only and request a ticket in the document.

Jake_Rosenfeld

@tony_soares459

We've had some similar trouble with thicken too internally.  Personally I've reported a sheet metal bug with a similar ripple, which was invalidating the "straight sides" that sheet metal are supposed to have in our system.

You could report a bug and we could pass it along to our geometry library.