When I delete a Circular Sketch Pattern It Breaks my entire Sketch

[oo7_golden_1]

I am hoping that a wise teacher can help educate me on a recent snag I hit in Fusion 360. I have searched and searched online and cannot seem to find a solution.

I have a sketch, it is relatively complex and has approximately 13 circular patterns. I accidently created a pattern that I need to remove from the sketch.

I thought that I could select the Circular Pattern Constraint, delete it, and then manually select the part of the sketch which the pattern generated, delete those parts of the pattern as well and then move on. Here is where the problem lies…

Since I have multiple Circular Pattern Constraints stacked on one another I have to hover over those constraints, hold left click, select the Circular Pattern Constraint in question but when I delete it… it breaks the entire sketch… and my sketch goes from fully constrained to not constrained at all.

I can even run the “Sketch.ShowUnderconstrained” in the text command field before trying to delete the Circular Pattern Constraint and its fully constrained. Once I delete that pattern everything becomes unconstrained. I cannot figure out why… I cannot figure out how to fix it…

Usually, I would try to use the modeling pattern feature under Create when building the model so that I can go back in the timeline and delete or edit the feature that was generated, but for this particular project that is not really practical and I think that I have to resort to using sketch patterns instead.

I have fought with this for a couple of hours now so I thought I would reach out for some advice…

Here is what I have already tried:

                I tried selecting the Circular Pattern Constraint and deleting it (with the delete button and by right clicking and selecting it from the options available) this breaks the sketch.

                I tried selecting the parts of the sketch that I wanted to remove and then manually deleting them… I did this both while editing the sketch and when simply viewing the sketch but I get a “Warning: Deleted geometry is part of a pattern, suppressed the instance or dissolved the pattern.” message. It also seems like the pattern constraint still exists despite all of its output being deleted… which I found odd.

                I tried selecting and then editing the Circular Pattern Constraint but when I suppress all of the patterns and deselect all of the instances setting the number to zero the Circular Pattern Constraint wont let me press ok to save the changes. This also happens if I remove the “Obects” or “Center Point” when editing the pattern. It makes sense why fusion would not allow me to fix it this way but I thought I would try it and it didn’t work.

                I thought that maybe the problem was that I didn’t place the center point correctly when I made the pattern in the first place as I could not choose the sketches Origin point as the Circular Pattern Constraints center point for some reason (does anyone know why that is as a follow up question?). To try to rule this out as the possible cause I selected the Circular Pattern Constraint, edited it and then tried moving the center point to a different point off to the side of the sketch and completely separated from the sketch and then deleting the Circular Pattern Constraint… it still breaks the sketch.

                I cannot delete the Circular Pattern Constraint in the parameters…

                I cannot seem to re-constrain my sketch either after deleting the Circular Pattern Constraint… I even tried deleting some of the other patterns that I didn’t want to delete and that seems to break everything as well…

Perhaps I am not generating the pattern properly when I create them? Maybe I am misreading that everything has become unconstrained… Since everything turns from black (constrained as I understand it) to blue (unconstrained as I understand it).

When I try to move anything in the sketch by holding right click and then dragging on a part of the sketch nothing seems to move… and the action of trying to drag the sketch registers because I can “Undo drag sketch” at the top left… I figured perhaps this might indicate that the part of the sketch I am trying to move is constrained despite it having a blue line but this isn’t the case as the “Sketch.ShowUnderconstrained” indicates everything has come undone and is now unconstrained?

I am not sure what I am misunderstanding, I do not know what I am doing wrong, and I do not know how I can go about trying to fix it.

Any advice would be appreciated.

[oo7_golden_1 · Accepted solution]

OK, a quick follow up after some additional fiddling.

If I edit the sketch, add a sketch point off to the side of the main sketch, select the pattern that I want to remove/delete, edit that pattern, move that patterns center point off to the side of the sketch by relocating its center point to the aforementioned sketch point I added earlier and then delete that patterns constraint it STILL BREAKS THE SKETCH… If I select a part of the sketch which the pattern created and deleted that selection and then try to delete the constraint it still breaks the sketch… BUT, if I select every part of the sketch which the pattern is generating and then delete the entire selection it will delete/remove that constraint and the rest of the sketch remains intact and fully constrained.

I still get the yellow warning message: “Warning: Deleted geometry is part of a pattern, suppressed the instance or dissolved the pattern.” BUT if I press the Finish the sketch button that warning goes away and my sketch is unbroken and remains constrained.

So, I think I am going to have to use this as my work around. I would still REALLY like to know what I am doing wrong to try to avoid such problems in the future. Why is deleting a circular pattern which nothing else in the sketch is linked to in any way shape or form causing the entire sketch to become unconstrained?

[g-andresen]

Hi,

1. please share an appropriate file for analysis. 

  >   File > export > save as f3d on local drive  > attach it to the next post.
2. check whether the patterns (especially because of the parameters) should not be executed more sensibly as a feature instead of in the sketch.
3. distribute the patterns over several sketches.

günther

[TheCADWhisperer]

It is said that a picture is worth a thousand words.

I might say that an actual file - the actual geometry - is worth a thousand pictures.

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply and end all doubt.

1. Are you fully defining your sketches?

2. Are you keeping your sketches simple?

3. Are you using computationally expensive sketch patterns where feature, body or component patterns would be more computationally efficient?

4. Are you using the BORN Technique as much as possible and practical?

[TheCADWhisperer]

@oo7_golden_1 

Where did you go?

[oo7_golden_1]

1. Yes, I am trying to fully define and constrain my sketches. At least to my knowledge.
2. No, My sketches are very complex but I don't believe that deleting a pattern that has nothing attached or constrained to it should cause separate parts of the sketch to become unconstrained...
3. I try to do that when possible but as mentioned in my original post (though I could have probably said it better) I could not do that in this particular project.
4. Yes, I make sure to link to my Origin point and use it as my anchor for all my sketches.

[oo7_golden_1]

Sorry. Got distracted. Thank you for your help guys.
I could not figure out why it was happening but I figured out how to get around it.
**See my follow up post for what I used as a work around if you are having the same problem and have stumbled upon this post through a search engine**