Sketch spline mirror fail

[N-9M]

In a sketch, I've drawn a spline between two straight lines at the ends, with a couple of control points in between. Tangency and curvature continuity constraints were applied to the ends, and the control point locations were fixed with dimensions.

Then I made a symmetric version of the straight lines, joined them with a new spline, and applied the same end constraints to the spline. I made the control points symmetric too. So the conditions should be exactly the same, in mirrored orientation:

The shapes of the splines should be perfectly symmetric, but as you can see if you look closely at the curvature plots, they are not.

I tried mirroring the spline itself, with the same asymmetric result. I also tried to delete the constraints and re-apply them, to no avail.

Is there any way to fix this? I have a feeling that it has to do with the influence of the curve connections, although unlike with Style or Round there is no influence length number to adjust. It's weird because the lengths of the straight lines are the same from left to right side.

I've talked with another engineer who ran into the same problem with similar geometry.

[MartinHanak]

Hi,

suggestion:

• create one half of curve
• mirror the curve feature

[BHOoi · Accepted solution]

I had the same issue long time ago and I found the best way to solve this is by geomtry/feature mirror. Creating symmetrical splines in sketch, either by applying similar constraints or mirroring simply do not work or you may run into symmetrical issue later. Creating one sketched spline only makes the sketch feature and subsequent features more robust and easier for modifications.