Sketch Origin from Offset plane problem\bug

[HughesTooling]

If you create a sketch on an offset plane the origin will be at the centre of the face the offset plane was created on\from. The problem is if the face is resized the origin doesn't update. Really the origin should either update or be created at the component origin in the first place. The way it works now seems rather dangerous. I would prefer it to update to the centre of the new face, maybe by reselecting the face like the screencast below. The screencast is pretty obvious when I increase from a 50mm wide face to 100mm, not obvious if you increase to 50.50mm though!

Thanks Mark

[jeff_strater]

Hi Mark,

I'm on my way out the door, but I will respond to this later.  There is a bit of debate about what the "right" behavior should be in in this case....

Jeff

[jeff_strater]

The longer version of the story is:  Fusion used to work pretty much like you described - sketches on a face, plus offset workplanes always had their origins at the center of the face (well, not always, at one time we looked for a "significant edge", and used that as the X axis).  But then, some people noticed that their sketches were moving around unexpectedly.  So, now, we try to keep the sketch coordinate systems as stable as possible on update.  So, one option would be to provide some preferences to allow you to say which behavior you want.

Now, I do agree with you that perhaps a better approach would be to always base a sketch's coordinate system on the owning component's origin.  And there is a project in our backlog to do that.  There are a number of other workplanes that behave unpredictably with regard to coordinate system that should also be cleaned up.  I'll bring this up again, and see if I can push for this a bit.

Jeff

[Anonymous]

Is there ANY way to circumvent this issue? It literally ruined a project I have been working on for 5 days now. I had to adjust the position of a whole in a sketch which in term moved the component attached on the one side of said hole. The whole stack on the other side however was created as an offset plane of the component that got moved. Which completely destroyed the project. Not only did the origin of that offset plane NOT move with the center of the the plane it was created, thus being off center, but since the moved component was also projected into the the stack on the other side to align holes, it's completely messed up. I have tried everything to get the origin to be on the correct position again, but nothing worked. "Redefine sketch plane" did not set origin correctly again. @jeff_strater  Is there anything I can do to save this?

Blue is the face of the part on the other side, the rectangle with the rounded corners top left and bottom right was created in the offset plane sketch on that blue face before it moved and is now wrong. The holes are aligned with the projected face, which is now completely messed up since the projection correctly moved but the offset plane's origin did not move.

[Anonymous]

I created a screencast depicting the core problem for me: https://autode.sk/3hfoe8d

First I just show that the origin does not move with the changed position of the original body after the circle in the sketch was moved, then I show that the projected circle does move while the origin does not, resulting in the projected circle in the second sketch being out of position. Which in term means, anything that depends on the projection or the origin being in the center will be completely messed up afterwards (which happened in my project)

[jhackney1972]

I believe where you are getting in trouble is that you do not tie the two component sketches together in any way during the creation of the second component sketch.  If you do this, even if you move the first component sketch, the second will always be related to it.

[davebYYPCU]

Your second component sketch at any stage of the video, 

has no correlation to the first component, you projected the big circle, after the small circle was created.

Make the 2 centre points coincident.

Redefine sketch plane only repeated the original definition, there was no change in it’s particulars.

Avoid 3d sketching, until you need it.

Might help....

[Anonymous]

Thanks for the replies - I think my issues is, that I was under the assumption, that the origin of the offset plane I create at 00:25 is tied to the center of the face (because it was created there and it automatically created the origin at the center) contrary to just creating the sketch directly on the face without an offset plane (in which case the origin is at the origin of the base component). Apparently the origin of the offset plane is NOT tied to that center which is something I was relying on. Sadly, I did this for a couple of successive sketches as well that all have a hole or something at the origin, which conveniently were the center of that circular face).  If I understand the answer by @jeff_strater correctly, this was how Fusion indeed worked a few years ago but the behaviour has been changed(?)

Do you know if there is a way to fix this for my current project once (moving the origin of the second sketch) or do I have to put in the hours and edit every single successive sketch and joint and constraint? From what I have read it's the latter, since origins seem to not be re-definable.

[davebYYPCU]

Without the file?  

I don't know how we can answer the question, you have a 1st sketch, and any further sketch was / is created for a purpose.  Seems that you have not projected from early to late, but expect that things will coincide for you without asking for it.

[Anonymous]

Well, it's the exact same problem as in the screencast. At 00:28 to 00:30 you see that the origin is in the center of the face of the first component, after moving the circle in the first sketch at 01:26 it's not anymore (at 01:33) - my question now is, can I get the origin of the sketch back to the center of first circle or is that just impossible?

[davebYYPCU]

So @ 28 sec, you are in component 2, have an offset plane placed on the top of component 1.  Create a sketch on that plane, the sketch origin appears on the centre of the plane and component 1 by fluke, and would do so if Component 1 was not visible, either.  So far no relationship to Component 1.

At the minute mark of the video you move Component sketch 1, and basically Component 2 doesn't care, doesn't follow on.

If - you wanted component 2 to always follow component 1 circle centre point, that centre point has to be projected into small circle sketch, AND you select that point for the centre point of small circle.  For reverse order, Project the big circle, and drag small circle to the centre point.

To fix a file that you did not do that, can be done.

Might help....