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Yet another C-Pattern User Parameter bug

Message 1 of 4
116 Views, 3 Replies

Yet another C-Pattern User Parameter bug

Design intent:

Take a base shape of a circle, but an arc of the perimeter of the circle is taken up by something:



Use a C-Pattern with a User Parameter ("NumSegments") to make a user-defined number of features that fill in the remainder of the perimiter


NumSegments = 4:



NumSegments = 6:



On to the problem...

I have a parameter CPatternAngle which works out what the "Angle" parameter needs to be in the C-Pattern.

This parameter calculates just fine and eg for 6 segments yields a value of -102.4deg




However, if I try to add it to the C-Pattern dialog, it is red and will not be accepted



I can, however, somewhat bodge it:

  1. open the Parameters window
  2. Create a new degree parameter (Called "Bodge" in this example)
  3. Set Bodge to an arbitrary value (Say 10 deg)
  4. Set the TotalAngle value of C-Pattern1 to Bodge
  5. Set the value of Bodge to CPatternAngle



Then everything works as expected. I can change the NumSegments parameter to what I want and the design dynamically updates.

Stranglely, if I close the parameter window and re-open it, then the C-Pattern TotalAngle param has turned red, but everything still works.



HOWEVER, if I save the project, close it, and re-open it, it no longer works, so this workaround is not an option


Message 2 of 4
in reply to: evilc

One of the requirements, rules if you will, currently in Fusion 360 is that sketch reference dimensions cannot be used outside of the sketch that they are created in.  In you case your first parameter is a reference parameter and you are then trying to use it, via parameters, to create a pattern which is outside of the reference sketch.  Hopefully this rule will change in the future but for right now, it is a limiting factor since it is an ideal way to read values from the model.


Sketch Reference.jpg

"If you find my answer solved your question, please select the Accept Solution icon"

John Hackney

Beyond the Drafting Board

Message 3 of 4
in reply to: evilc

The bug behavior is related to the driven user parameter.
If that driven user parameter is not used but the TotalAngle is calculated

(180 deg - asin(d5 / ( d7 + CircleDiameter / 2 )) then it can be used within other formulae without a problem.

Peter Doering
Message 4 of 4
in reply to: evilc

OK.... seems very odd, given that I can get it to work (Albeit only until I reload the project) with the "Bodge" technique though...

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