Redefine Sketch Plane: Preview looks fine, then FLIP!

[robduarte]

Sorry, I made this screencast with the intention of sharing the design.. then I closed without saving by accident. I thought I had to share the screencast anyway, in case someone has a logical explanation for what seems like a crazy bug.

https://youtu.be/BpektFpoATY

[laughingcreek]

There is a similar bug (bugs) where the orientation (x and y axis of the sketch) of the sketch changes after the first edit in certain cases.  I can't remember the posts at the moment where they were reported, but I'd be curious to know if this is related.  If your able to reproduce this again, you might check and see if the sketch axis direction is changing.  @Anonymous, what do you think? 

[robduarte]

I just crossed my fingers and tried to recreate the problem from scratch but of course I can't get it to fail now. 😞

[jeff_strater]

Redefine Sketch plane, I agree, has some issues.  This command orients the sketch plane so that the coordinate system in the new sketch is similar to that in the old sketch.  If the destination planes align pretty well, it works out OK.  But, if the normal is in another direction, it can often flip around in surprising ways.

What is needed, IMO, is some tools to help you select the X and Y axes for a sketch, either during the Redefine Sketch Plane command, or afterward.  In my opinion, this command is of limited use because of these types of problems.

Jeff

[robduarte]

What do you suggest as an alternative? Out of the yellow-warnings-on-the-timeline, this specific one seems to be the most frequent. If Redefine Sketch plane isn't currently useful, then how would you recommend going about fixing the issue where a sketch has lost its reference plane?

[jeff_strater]

I'll qualify that a little:  Redefine Sketch Plane is most useful when the new and old plane are fairly well aligned.  And, hopefully, that is the case when you are using it to fix a broken plane reference.  Yes, this is really the only tool (short of just redrawing the sketch) that is available for repairing a broken plane reference.

Where it doesn't work well is when doing things like redefining a sketch from one area of the model to another.  Or, if moving a sketch from a body face to a workplane (some work plane types have different inherent coordinate systems).  

Further, when this command does produce an unexpected result, you can usually get it pretty close by moving the geometry, and re-establishing some dimensions or relationships between the former projected geometry and the new face's edges:

I'm not saying this is great, only that you can usually get it to work for you.  I am definitely in favor of improving this commands.

Jeff

[CruftMeister]

@jeff.strater

Hey Jeff, is there a timeline for fixing the Redefine Sketch Plane command?  At this point, even moves that should be trivial yield disastrous results i.e. end result is too broken to salvage so I delete the sketch and just start over.  I have yet to use this command successfully, irksome as it works so well in Solidworks . . .

[mavigogun]

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@jeff_strater wrote:

I'll qualify that a little:  Redefine Sketch Plane is most useful when the new and old plane are fairly well aligned.   *snip*  I'm not saying this is great, only that you can usually get it to work for you.

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Not today- or yesterday: redefining to closely associated parallel faces continues to radically reposition elements; my previous work-around- cluttering the design by creating a target construction plane -is yielding the same results.

[Anonymous]

Not fixed over a year later, either. It's always disheartening to see obvious bugs live on for so long.

[mavigogun]

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@Anonymous wrote:

Not fixed over a year later, either. It's always disheartening to see obvious bugs live on for so long.

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This is going to sound totally wacked, but the SIDE of the Plane you select matters.   Try the problem Redefine twice, each time selecting from the opposite side of the target Plane, and see if the results are the same.   Oh- and report back!

[Anonymous]

I did, and it didn't work. Doesn't matter, though, and all of @jeff_strater's comments last year were meaningless. Because here's the trick - this post wasn't specifically about Fusion's internal logic getting the new sketch wrong. That would be annoying but understandable - 3d geometry is hard, and users aren't thinking about the internal logic.

This is about the preview being right, but the actual redefine being wrong.

That's a bug, no matter how you slice it. And yes, my preview showed exactly the sketch plane movement I wanted. It just flipped upside down when I pressed "Okay."

[lindsay.fowler]

This sketch flipping issue hasn't been fixed at all. Even when a sketch is based on projected geometry, redefining the sketch plane flips the sketch and breaks its reference to the projected geometry. Totally inadequate. If you define the wrong sketch plane by mistake, then spend 30min doing a sketch, well you can kiss that time goodbye, because you will be doing that whole sketch again. Frankly, Fusion is fantastic for knocking up great designs quickly, but try and edit them - particularly when you are dealing with references - and you are entering a world of pain. Oftentimes it is quicker to just do the whole design again from scratch. True story

[mavigogun]

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@lindsay.fowler wrote:

Even when a sketch is based on projected geometry, redefining the sketch plane flips the sketch and breaks its reference to the projected geometry. Totally inadequate.

No contesting that pain. That said, considering the critical nature of perspective to Projections, it makes complete sense for them to become De-Linked. Actually, I thought what you've described might be USEFUL for breaking all Projection connections in a Sketch without the tedium of selection, by selecting the original plane for the Redefinition- however, the result is absolutely bizarre! Some portions are not De-Linked, while others have the Fixed Constraint applied to them! We can see this in the following image, where the Cube was 3D Projected to the Sketch. Using Primitives was probably a lousy choice for the experiment, considering all the implementation failures associated with those tools.

[lindsay.fowler]

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@mavigogun wrote:

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@lindsay.fowler wrote:

Even when a sketch is based on projected geometry, redefining the sketch plane flips the sketch and breaks its reference to the projected geometry. Totally inadequate.

"..considering the critical nature of perspective to Projections, it makes complete sense for them to become De-Linked."

But @mavigogun, I'm talking about an offset plane! 🙂 So there is no shift in perspective and the projections do not change.. How could it lose orientation, position, references?? It's just madness - No, it's buggy!

[mavigogun]

Oh, ya- the flipping and re-orientation is almost certainly a fault; I was just musing that Breaking the Projection in that circumstance seemed... expected.   Lacking that, depending on the Projection direction and parallel plane, it doesn't follow that there would be a break- though that may depend on when the Redefinition happens in the Timeline; does the Break, lacking any orientation change, still occur if the Redefinition happens before the Projection in the Timeline?    Is that a contextual possibility?

[Anonymous]

Still no solution to this problem. I would say this was a pretty serious issue and am very surprised it's still around.

[geoffUUV2R]

Glad I saw this thread - I often get the same problem... I thought it was me! There seems to be no rhyme or reason to it.

[C.Nicks]

I'll just bump this thread and add that I almost can never redefine a sketch plane without everything flipping upside down. I've tried creating construction planes parallel to the old sketch plane and it still just flips everything over. Haven't found a single workaround yet. Quite frankly this is a major issue that is getting in the way of being remotely productive with Fusion. I've spent all day trying to get a simple sketch to behave, something that can be done in other professional tools in a matter of minutes.
This is a glaring bug that's clearly been an issue for a long time. Please can someone get on this.

I tried to capture a gif to show what it's doing when attempting to redefine, but for some reason the Fusion app rendering is invisible to recordit (Mac).

[TrippyLighting]

Use plane-at-angles because by changing the angles you can flip the sketch.

This is certainly an annoying issue when it arises, but if it's a major obstacle to you being productive then your general workflow likely has other issues.

[lindsay.fowler]

I’ll look into plane-at-angles. Thanks. Still, why doesn’t Fusion just remember the orientation of the sketch, just as it remembers everything else in the sketch?