topic Re: Symmetry Collapse Sketch Bug in Fusion Support Forum

Symmetry Collapse Sketch Bug

glrra30 — Mon, 16 Oct 2023 17:59:19 GMT

Sketching on face of body. Use Symmetry to center another line between an edge and another dimensioned line.

Now add another line parallel to the lines with symmetry. Symmetry collapses and dimension changes.

If you delete the new line the symmetry returns. Was having this issue in another model, but was sadly easy to recreate the issue in a new Design.

Re: Symmetry Collapse Sketch Bug

g-andresen — Mon, 16 Oct 2023 18:51:57 GMT

Hi,

I have removed all lines and recreated them according to your scheme, and the described error does not occur.

günther

Re: Symmetry Collapse Sketch Bug

glrra30 — Mon, 16 Oct 2023 21:38:11 GMT

Same order of operations? All the lines on the right, then the symmetry, the line on the left last?

I'm on a Mac, maybe it's Mac-specific?

Re: Symmetry Collapse Sketch Bug

g-andresen — Mon, 16 Oct 2023 21:52:03 GMT

Hi,

did you remove the actions once and repeated them completely in the same way?

günther

Re: Symmetry Collapse Sketch Bug

glrra30 — Mon, 16 Oct 2023 23:44:57 GMT

Deleted all the elements in the Sketch, repeated the actions. Same behavior.

If I wait until after drawing the line on the far left, then apply the Symmetry to the three lines on the right it doesn't collapse. That doesn't make it not a bug. You should be able to add an element to a sketch without the previously fully constrained elements failing.

Re: Symmetry Collapse Sketch Bug

davebYYPCU — Tue, 17 Oct 2023 00:07:18 GMT

Repeatable on a Windows machine too.

Might help...

Re: Symmetry Collapse Sketch Bug

g-andresen — Tue, 17 Oct 2023 05:36:13 GMT

Hi,

that´s what I see

(view in My Videos)

günther

Re: Symmetry Collapse Sketch Bug

glrra30 — Tue, 17 Oct 2023 17:34:33 GMT

To recreate issue: draw line at 75mm from right first, dimension, then draw center line between far right and line at 75mm. Add Symmetry. Sketch should be full constrained at this point with projected surface boundary, one dimension, and symmetry constraint. Now add line on far left. Collapse . . . .

This is different than your video above where you delete the line at 75mm from right . . . .

Re: Symmetry Collapse Sketch Bug

g-andresen — Tue, 17 Oct 2023 18:10:17 GMT

Hi,

symetry in clean sketch

(view in My Videos)

günther

Re: Symmetry Collapse Sketch Bug

glrra30 — Tue, 17 Oct 2023 19:07:43 GMT

@g-andresen, evidently the horizontal centerline is necessary to trigger the problem.

1)New Sketch on face.

2) Project edges of face.

3) Vertical line @ 75mm from right. (trim as needed)

4) Dimension (3) to 75mm

4) Horizontal line from mid-point (3) to mid-point far right.

5) Vertical Centerline (trim as needed)

6) Symmetry (3) & (5)

7) Draw vertical line to left of (3) . . . . collapse

Re: Symmetry Collapse Sketch Bug

g-andresen — Tue, 17 Oct 2023 20:23:37 GMT

Hi,

In the meantime, I tested different scenarios and found that the behavior shows up in other sketches as well.
Result:
1. the error does not always occur
2. it occurs only in combination with projected sketch elements, but not with sketches without projections.
3. the symmetry line "seems" not to play a role.
4. moving the outer line activates or deactivates the effect.

I will report when I have new insights.

günther

Re: Symmetry Collapse Sketch Bug

davebYYPCU — Tue, 17 Oct 2023 20:56:31 GMT

For me that’s a bug, it’s repeatable. @jeff_strater Should not happen, but it does.

Those of us been here a while use other constraints to get it done,

Don’t hold your breath waiting for sketch engine fixes.

Avoid symmetry and mirrors if there are more robust methods.

constrain the middle line to the centre of the construction line.

Might help….

Re: Symmetry Collapse Sketch Bug

g-andresen — Wed, 18 Oct 2023 16:02:59 GMT

Hi,

Currently it looks to me that the described behavior only occurs when the symmetry contains a projected line.

(view in My Videos)

If you replace it with an independent line or remove the link, the error does not occur.

günther