Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.
First time visiting? Here are some places to start:- Looking for a certain topic? Check out the categories filter or use Search (upper right).
- Need support? Ask a question to our Community Support category.
- Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
- Be respectful, on topic and if you see a problem, Flag it.
If you would like to contact our Community Manager personally, feel free to send a private message or an email.
Wrong geometry applying features on a curved pattern
outstanding
Member Posts: 56 ✭✭
Expectation:
- also in the curved section, the sketches stay inside the pipe and follow its alignment
Actual:
- as in the picture. Note that the alignment is back to correct in the straight tail (extension of)
I need this for placing equidistant holes on a pipe. Using sketches just shows the - what to me seems like a miscalculation of geometry - with minimal complexity.
Let me know if this indeed is a bug or if I'm using the tool wrong.
Reproduce:
Related:https://forum.onshape.com/discussion/4143/pattern-feature-along-curved-surface-following-tangent
0
Comments
In reviewing this document I noted this notice. Looks like this is what is causing an over shoot on curve pattern.
Made a new curve path from original with the end trimmed off to the seed feature. That made the the curve path work out.
https://cad.onshape.com/documents/96a7e36864680c877c5c8c06/w/4c387e09608cc2e7441ee5fc/e/12075c5f214c083aca0f0663
I would still say this is a bug in the current implementation and your proposal can be seen as a valid work-around.
Why this matters is that Onshape is remarkably consistent and expectable, especially when it comes to geometry. I don't usually need to think "like the tool does" or do work-arounds. (read this as: I do them, but less than in competing products). I'd like to keep it that way and help Onshape by reporting things were such consistency seems lacking.
Would you agree - is Onshape seeing this as a bug?
It's literally doing exactly what you are asking by adding instances of the feature along the path, respecting the relationship between the starting point of the path and the location of your "seed" feature.
What if you needed the feature you are patterning to not actually intersect the path, what should Onshape do then? I'd rather have the current behavior than see Onshape "interpreting" the path in potentially unexpected ways.
The only thing that might be a bit counter-intuitive is if you are comparing this to a sweep but the sweep is continuous along the path so there is no ambiguity about what to do along the length. for example, if this worked like a sweep then you could argue that the first instance should "move" to the start of the path or the pattern should go along both directions of the path, which would produce the same result for a sweep but neither of which are what you actually want here.
This is more analogous to what happens when your profile is offset laterally from the sweep path and weird things can happen.
You are asking Onshape to read your mind and decide to ignore part of the path, which would lead to unpredictable behaviour.
Not sure I'd agree with the bug analogy. May be, it could could go as an IR for more flexibility like an off set start so the same sketch can be used. Some of the other functions have that kind of functionality built in. My other sample that has a move face at the tube start to use same sketch for all is not my favorite. Kinda a break in the flow.
It's literally doing exactly what you are asking by adding instances of the feature along the path, respecting the relationship between the starting point of the path and the location of your "seed" feature.