topic Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior? in Fusion Design, Validate & Document Forum

Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior?

shreenivaspotnis — Wed, 08 Apr 2026 09:44:48 GMT

I’m observing some inconsistent behavior when using Redefine Sketch Plane in Fusion 360, and I’m trying to understand whether this is expected or if I might be missing something.

Scenario

I created a sketch and later attempted to redefine it onto different construction planes.

Case 1: Plane Along Path

The sketch appears to rotate correctly about the intersection axis
However, it also undergoes an additional ~90° rotation about the plane normal

This additional rotation was not expected

Case 2: Plane at Angle

Again, the sketch aligns along the expected axis
But it additionally flips/mirrors itself

This makes the final orientation difficult to predict

Question

Is this behavior expected due to how Fusion defines the local coordinate system of a plane?

It seems like the mapping of the sketch depends on an implicit X/Y orientation of the target plane, which is not visible or user-controlled.

Observation

From a user perspective, this results in:

Non-deterministic orientation after redefine
Trial-and-error to get the desired result
Difficulty maintaining design intent across planes

Thought / Possible Direction

Would it make sense (now or in the future) to allow some level of control over how the sketch is mapped onto the new plane?

For example:

Rotate about the plane normal (90° steps or user-defined angle)
Flip / mirror orientation
Optionally, provide an additional control during plane creation (or edit) to refine the plane’s coordinate system via a pop-up, including:
- Normal direction
- Origin location
- X and Y axis directions

Even a minimal level of control could make the behavior more predictable and reduce trial-and-error.

Note

I can create and share a minimal test file if that helps reproduce the behavior.

Closing

Would appreciate clarification on whether this is expected behavior, a limitation, or if there’s a recommended workflow to control orientation more reliably.

Re: Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior?

davebYYPCU — Wed, 08 Apr 2026 09:57:27 GMT

Been here 8 years and it was the same problem back then.

Not fixed.

There have been explanations from the boffins, but it's apparent they don't have a need to fix it. (Priorities, you know)

Workaround, - don't use it or put up with it.

Might help....

Re: Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior?

shreenivaspotnis — Wed, 08 Apr 2026 13:02:55 GMT

Thanks for sharing that—interesting to know this has been around for a while.

I’m trying to understand whether the behavior is fundamentally due to how the plane’s local coordinate system is defined internally, or more of a UI limitation (i.e., a lack of control over that coordinate system).

From what I’m observing, the main difficulty is not the redefine operation itself, but the inability to control or even see how the X/Y orientation of the target plane is chosen.

If that’s the case, perhaps this is less about “fixing” the current behavior and more about exposing some level of control (even minimal), such as:

Rotate about the plane's normal
Flip/mirror orientation
Define a reference direction or axis on the plane

That might make the outcome more predictable without changing existing workflows.

Curious to hear if others have found a reliable way to control the orientation, or if this is generally handled through trial-and-error.

Re: Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior?

jhackney1972 — Thu, 09 Apr 2026 01:12:51 GMT

If you already have the new UCS (User Coordinate System), you can use it to create your new Origin and use one of its planes during the Redefine Sketch. The UCS displays the "positive" directions for all of the planes so you can better predict the sketch response during the Redefine Sketch command. If you do not have the UCS command yet, you may not have turning it on in the Preview Features of your Preferences.

Re: Redefine Sketch Plane: Unexpected Rotation / Mirroring — Expected Behavior?

HughesTooling — Thu, 09 Apr 2026 10:21:56 GMT

Something else to be aware of is redefine sketch plane will also break the link for all projected geometry and set it to locked without warning. I you want really bullet proof designs you should never sketch on a face directly, always create a plane then sketch on the plane. If the reference is lost just resect the plane's reference face and projected geometry will be maintained. Also as long as the new face you select has the same orientation you should have less problems with the sketch flipping.