BUG - Inventor Causing a Cyclical Dependency by Consuming Sketch

[andrewdroth]

By changing a Contour Flange input to a linked parameter it causes the feature to consume the defining sketch without sharing. This causes a cyclical dependency and corrupts the browser.

I had this happen on another sheet metal master part, but I didn't notice right away and it wasn't until I tried to move the EOP marker that I found out about the cyclical dependency, and even then it wasn't clear what cause it. I ended up losing a lot of work by needing to start over on the features below the problem.

Please fix!

[Xun.Zhang]

Hello @andrewdroth,

Thanks for the data and detail steps, it was tracked as ticket INVGEN-22952 for now.

Please stay tuned and Hope it helps!

[andrewdroth]

Thanks Xun,

Were you able to reproduce the problem with the example given?

[jletcher]

It is not a bug where you think.

You are putting the cart before the horse you can say.

You are linking a feature to a sketch before the sketch with the dimensions.

Sketch 16 is your profile, sketch 17 is your dimension it needs to be the other way.

It should never have let you pick that dimension at all the and that is where the bug is.

[andrewdroth]

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@jletcher wrote:

It is not a bug where you think.

You are putting the cart before the horse you can say.

You are linking a feature to a sketch before the sketch with the dimensions.

Sketch 16 is your profile, sketch 17 is your dimension it needs to be the other way.

It should never have let you pick that dimension at all the and that is where the bug is.

---

No that's not right.

The feature is below the sketches and that's all that matters.

Sketch 16 isn't consuming the dimension from Sketch 17. (And that is also doable as long as it doesn't cause a cyclical dependency)

[andrewdroth]

See, it's perfectly fine to do.

[jletcher]

@andrewdroth Wrote:

No that's not right.

The feature is below the sketches and that's all that matters.

Sketch 16 isn't consuming the dimension from Sketch 17. (And that is also doable as long as it doesn't cause a cyclical dependency)

 You can post all the videos you want this is where your issue is.

In Sketch17 you used sketch16 projected something to locate sketch17

Now you are asking inventor to forget about sketch 16 when you drag the end of part up issue is sketch17 uses sketch16 without it you created a cyclical dependency with the sketch not dimension.

Read the error it is not a error with the dimension but a constraint error with the sketch.

[andrewdroth]

I think you need to re-read my initial post. 

Sketch 16 is above sketch 17, and everything is hunky dory, but when I create that feature it fully consumes sketch 16 (which it shouldn't do, it should remain a shared sketch.) which pulls the sketch from being above sketch 17 down to where the feature exists. This is what causes the cyclical dependency. not the fact sketch 17 relies on sketch 16.

[jletcher]

Don't need to re read..

Here is your part back with sketch16 bellow your sketch17 and there are no issues.

You can now drag end of part past the feature and it works, try to drag it past sketch16 it does not.

In all I would never do your workflow for these reasons.

[andrewdroth]

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@jletcher wrote:

 You can post all the videos you want this is where your issue is.

See Screencast. 

Notice how the sketch named 'Horse' is not pulled below the sketch named 'Cart'?

That is because IV recognizes that it isn't possible.

Now look at my original screencast, it does exactly that, and there is the problem. Sketch 16 should not be allowed to be below sketch 17. Same with the horse following the cart.

[Lewis.Young]

Yes i agree with what you're saying. I couldn't open your file as i'm on an older release, but if sketch17 is using projected geometry from sketch 16, then it's impossible for 16 to be below 17 in the browser.

The only time i can get it to fully consume the sketch is when the contour flange is created using a sketch (sketch 16), the EOP marker is then moved up above the feature, a new sketch is created (sketch17), the EOP moved back down below the contour flange and then the feature's edited to use the sketch 17 dim as the distance.

Unless you've done that, i can't see why it would be fully consuming it and not sharing it...

Hopefully @johnsonshiue can give a clear answer, instead of passive aggressive responses from other people...

Lewis Young
Windows 7 x64 - 32GB Ram
Intel Xeon E5-1620 v2 @ 3.70GHz
nVidia Quadro M2000 - 4GB
Inventor Professional 2017.3
Vault Basic 2017
3ds Max 2018

[andrewdroth]

Thanks Lewis!

I didn't do anything funny to get the cyclical dependency, just normal workflow.

I do move the EOP marker up and down a lot while modeling though. And what is weird is it didn't give me an error until I tried to do so.

I can even fix the issue by moving Sketch 16 back up to it's original location which should rule-out any concerns about workflow.

[jletcher]

@Lewis.Young Wrote: I couldn't open your file as i'm on an older release, but if sketch17 is using projected geometry from sketch 16, then it's impossible for 16 to be below 17 in the browser.

Then I can do the impossible

@andrewdroth wrote:I had this happen on another sheet metal master part, but I didn't notice right away and it wasn't until I tried to move the EOP marker that I found out about the cyclical dependency,

Strange you keep doing the same thing over and over and you keep getting the same results.

See this is why I am telling you the bug is not were you think it is. Inventor should never have allowed you do do this.

But you keep corrupting your files they are your files.

I am sure Autodesk will figure out a way for you to keep doing it wrong, they did it for axis mate constraints.

 Have a good day you 2.

[andrewdroth]

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@jletcher wrote:

But you keep corrupting your files they are your files. 

---

How did I corrupt my file? 

Are you saying that creating a feature with a profile from one sketch and a distance dimension from another is poor modeling practice?

[jletcher]

Can you drag the end of part past your feature?

There is your answer.

Not saying you can't do what you are doing but you are getting the result you asked for.

To me this is a corrupt file, if I can't drag end of part all the way to the top.

Again it is not so much the dimension but the projected geometry .

 Share sketch is for features not for projected geometry in another sketch.

[andrewdroth]

I don't know what to tell you. Look at my last screencast. I fixed the part you posted by moving the sketch back where it belongs. I can then move the EOP wherever I want.

The bug IS that IV moves the sketch out of place. Obviously a sketch that has projected geometry needs to be below the sketch it is projected from. Nobody is arguing that.

I've been modeling this way for a long time and these past few weeks are the first time I've seen IV do this. I don't know if it has to do with IV2019 or the contour feature it'self. I haven't used either very much. But I do know that this workflow doesn't usually end up in corrupt parts.

[jletcher]

@andrewdroth Wrote:

I had this happen on another sheet metal master part, but I didn't notice right away and it wasn't until I tried to move the EOP marker that I found out about the cyclical dependency, and even then it wasn't clear what cause it. I ended up losing a lot of work by needing to start over on the features below the problem.

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Yeah seems to work for you, again if you want to take the chances go right ahead.

Yes you can drag the sketch16 back up but if you edit the feature you will have error again.

 Even where I have it if your edit the feature it will happen again and again and again and again and again and again and again and again and again 

oh snap now I am stuck.

I will say this again, Inventor should never have let you do that and that is where the bug is.

I wish you the best of luck.

[andrewdroth]

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@jletcher wrote:

It is not a bug where you think.

You are putting the cart before the horse you can say.

You are linking a feature to a sketch before the sketch with the dimensions.

Sketch 16 is your profile, sketch 17 is your dimension it needs to be the other way.

It should never have let you pick that dimension at all the and that is where the bug is.

---

You've changed your opinion since posting to this thread then.

Yes, I had it happen on another part A WEEK BEFORE. but I didn't know what had happened on that other part until I saw it happen on this one. It was my Ureka! moment.

You are right that editing the Contour Flange Causes brings back the error. And that is the BUG! just as the post is titled 'Inventor Causing a Cyclical Dependency by Consuming Sketch'. That feature should not be moving and consuming the sketch. The sketch should stay were it is and should be in a 'shared' state.

[jletcher]

It was easier to say dimension because I did not want to spend all day trying to explain it was a projected geometry and you tell me I am wrong like you are.

 This is your issue you can learn from it or sit here till Autodesk figures out a way to make it work and I don't see that happening, they are too busy messing up the interface.

Flip the 2 around and you will never have issues.

Best of luck to you.