Sketch entity copy problem

SledDriver

Try as I might, I don't understand what is going on here.

In this drawing https://cad.onshape.com/documents/5886c8af08ee0a0fe07320c1/w/b77b7bb9d77a77b8740df4fe/e/0ce9691cf8f7377345d8bfc1

I first sketched the Original lines which are fully dimensioned and constrained, fully defined and referenced to the origin.

When I do the first copy of the entities the copy is at first not fully defined as expected until I give it dimensions from the origin, then it too becomes fully defined.

However, When I do the same to the rotated copy, including dimensioning the angle of rotation, the entities stay mostly not fully defined, and I cannot see why. All the constraints are still present, and the dimensions, but it remains mostly blue.

Can anyone explain this for an OnShape novice. I've researched at length and just don't get it.

Cheers,
John

owen_sparks

Hi @john_mccurdy.

You're missing the dimension of the width of the base.  With that added the rotated sketch becomes fully constrained.

Owen S.

SledDriver

OK Thanks for that. But I don't understand why that base is not dimensioned.

In the original, the base width IS defined - I dimensioned half the base and mirrored it.

Also that dimension is maintained in the first copy. Just not in the rotated copy.

I don't understand why one would work and the other fail just apparently because it is rotated?

owen_sparks

I take your point.

Here is a copy process of the entities.  So far we've copied and pasted and have started a rotate function. Note the 46.198 dimension:- at the base.



As soon as we click to accept the  25 deg rotation the dimension is removed.



Owen S.
 

owen_sparks

Interestingly if you delete the problematic dimension, and instead add a construction line, and then dimension to that then all is good even after the rotation.



Owen S.

SledDriver

Thanks for that. Hmm. This all seems a bit inconsistent and error prone in a complex sketch.

I'm trying to ascertain whether it is my lack of understanding or a bug. The mere fact that the outcome is different just by adding the construction line is a bit worrying!

It leaves the questing, when is a fully defined object still fragile... Doesn't seem too good.

SledDriver

I contacted support, and they believe there is possibly a bug in the entity transform command, which they are now looking into.

owen_sparks

Thanks @john_mccurdy, I'd agree on the "its a bug", not a lack of understanding.  If we dimension something it would be ideal if it stayed dimensioned! 

Great to see an immediate response from OS.

Cheers,

Owen S.

emmett_weeks

The issue is that directed distance dimensions get deleted on transforms that are not multiples of 90 degrees. Directed distance dimensions are dimensions between two points along the x or y directions.

As a workaround until the bug is fixed, try to avoid adding those before transforming a sketch.