Sketch Rectangular Pattern copies not copying all constraints

[tiktuk]

Hi,

I am trying to make a rectangular pattern from a simple spline curve. The strange thing is that the constraints on the spline handles are not copied in the pattern?!?

Notice how the handles are constrained to be horizontal/vertical in the original and the normal copy/pasted curves, but not in those in the pattern. They also lost their size constraints 😟 .

Is this a bug or am I doing something wrong?

[innovatenate]

The constraints/dimensions not appearing with other instances of a sketch pattern is an intentional behavior. In the below screenshot, I'm applying a sketch pattern to a rectangle with vertical/horizontal constraints. In does not really make sense to persist the constraints for two reasons.

• Constrains/dimensions can conflict with the pattern (in the below example, the rectangles could not be rotated about the center-point as needed)
• There is a pattern constraints that will allow instanced sketch pattern geometry to be automatically updated based upon the original sketch geometry. This negates the need for additional, redundant constraints on each patterned entity in the sketch.

I hope that helps! Please let me know if you have any questions.

Thanks,

[tiktuk]

Thanks for your quick reply!

That makes sense. But I still can't make a pattern with splines that copy directly, even though I don't use constraints.

The handles lose their direction either way.

Can you make patterns from splines that stay true to the original?

[innovatenate]

Okay, I see the issue now! The tangent handles don't really seem to be fully supported in the sketch pattern. The behavior seems fairly consistent and I believe would fall into the category of a feature enhancement, which can be request on the Fusion 360 Ideastation. If you add an idea, please put a link here and I will add my vote to it. It would be awesome if the pattern command would support the tangent handles for splines.

There is a work-around you can use to force it to work. I've made a short Autodesk Screencast below to highlight the steps required. 

Please have a look and let me know if you have any questions. 

[tiktuk]

Thanks for the screencast ☺️ !

I want the quantity in the pattern to be driven by a parameter so I can't do manual work on the copies though 😟 . But nice workaround otherwise.

I guess it's not possible right now, then. Also, to me it seems to be a bug rather than an enhancement. I would never expect only part of the curve to be copied. And the handles are certainly parts of a spline, I would say. Like regular copy/paste does…

Thanks for all your help, again ☺️ .

I submitted to IdeaStation here.

[hammerquill]

This "intentional behavior" is awful.

I have created a complex sketch object. It is carefully constructed so that one dimension change will alter the whole object to scale it correctly. I need to create dozens of these across the sketch plane, then break the pattern constraint (which should be possible during the pattern creation by unchecking a box, but anyway...), then resize most of the copies. But if I do this, the resizing doesn't work, because ALL, 100% of the constraints, have been removed during the copying. So if I change my one work circle geometry in a pattern copy (which in the original sketch object will scale everything correctly) it has no effect on anything else. So in order to do this simple operation - COPY - I have to copy, then go through and create from scratch a dozen or more constraints, almost all of which were never explicitly applied in the first place, but implicit. And I have to do this literally hundreds of times because there are many copies. Surely, surely there's a better way to have designed this. Like, with checkboxes letting the user decide what gets copied. Always. Everywhere. In the rare instances where this would create errors, an error should pop up and let you change your decisions. I wish this sort of thinking was considered the standard, but it does not seem to be in this program. Ever.

[TheCADWhisperer]

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@hammerquill wrote:

I have created a complex sketch

then break the pattern constraint

 And I have to do this literally hundreds of times because there are many copies. 

---

@hammerquill 

In parametric modelers - sketches should be kept simple.

A broken “pattern” is not a pattern.

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

Can you find a picture of something similar to your Design Intent that already exists in the real world and attach or link it here?  There might be an easier technique.

[g-andresen]

Hi,

I can only recommend you to make patterns not in sketches but from features; faces; bodies.
If the pattern is created in sketch mode, the changes to the resulting features must be made manually if the quantities are changed.

günther

[hammerquill]

It is pretty simple, in fact. It only becomes complicated when you remove all the constraints that were applied implicitly during the creation of the original, and every part of it becomes separate. Which is the program's behavior that I'm complaining about.

Here's an image of my sketch, showing one possible result of applying some but not all required constraints to the second instance before altering the key dimension.

The required geometry is a circle with indents. The indents are simple triangles of a given height (1mm). The defining dimension needs to be the diameter of the inner circle which goes through the points of those indents. So, I created a construction circle with two construction radii for reference (only really needed one). I then created another concentric circle outside that and defined the distance between the two.  The indents were created by drawing one line, mirroring it, then selecting those two lines and creating a circular pattern. I then broke the outer circle to make the resulting profile simple, while retaining the work geometry so that no references would be lost, so the copies could be altered correctly. Or so I thought.

I then created a rectangular pattern of these objects. After searching again to see if they had yet implemented a checkbox to de-link them during the process of creation (sigh), I figured out how to delink them again afterwards in order to be able to resize each of the others (and why can't I delink just one instance? Nevermind). I then dimensioned the second instance by dimensioning the inner construction circle. But it didn't work. It simply changed that circle's diameter and left all the actual geometry I cared about untouched. I tried many solutions to fix this. If I defined the dimension on the distance between inner and outer circles first, it only applied to one outer arc at a time. If I explicitly dimensioned the difference between the inner circle and each outer arc (as shown in the screenshot) it still ignored the coincident constraints on the points of the indents.

If I go back and attempt to explicitly select every single constraint, first of all, they are hard to find, and always unnecessarily hard to identify, and second, it doesn't seem even to have a constraint selectable for the points of the indents. But in any case, even with them selected, they won't copy to the rest of the pattern. This should absolutely work when explicitly requested by the user. (Same for dimensions.)

[TheCADWhisperer]

@hammerquill 

Just as I expected - you are doing this the hard way.

[hammerquill]

Wow. That's helpful.

[davebYYPCU]

As we don't know what you are making, as far as I would go until more detail is announced.

Copy / paste each individual sketch set.  You don't lose the constraints, and the dimensions can be edited.

Pattern each set, and they will be fully constrained.

Might help....