Dimension Arc Length in a Sketch

[Anonymous]

Hello,

I want to sketch an arch of a defined length, but it only lets me dimension the point to point length (see below). I don't see a way to do so other than calculating it manually.

Is there an easier way?

Thanks!

[paul.clauss · Accepted solution]

Hi @Anonymous

Thanks for posting! Unfortunately there is not currently a tool in Fusion 360 with which to dimension an arc length in a sketch. This option has been discussed on the Fusion 360 Ideastation and is gathering support - please give it a vote!

To find the arc length of a sketched arc, you can use the Inspect > Measure tool and select the arc.

There is also a way to parameterize the arc length in the sketch - this may work for your design. Hopefully it will help! Feel free to reach out if you have any questions.

[Anonymous]

Thanks for the response!

[g-andresen]

Hi,

It is important to record all extended lengths, not just arc lengths.

günther

[Farzati.Scott]

Seems a lot of things that should be included or implemented are just discussed without any action taken.  Have seen various messages posted that go back years and are still waiting.  Fusion 360 should be a program that can be used in the real world  from design to manufacturing.  However the main focus is creating models for presentation purposes only.  Sort of gets disappointing as well as frustrating...

[HughesTooling]

@g-andresen Have you used a parametric program that allows setting the length of a spline in a sketch and if so how does it work? Or do you just want the ability to dimension the length on your 2d drawings?

Just checked ZW3d and Alibre and neither has a dimension tool for spline length in a sketch and only ZW3d has an arc length dimension so Fusion's not that lacking.

Mark

[Farzati.Scott]

AutoCAD has many features and options including doing a arc length. Oh
wait Autodesk makes Fusion as well. So why not incorporate as many
capabilities as you can into the CAD/CAM of Fusion? I mean it must have
already been solved. Especially when users are looking for this feature.
Jus sayin...

[Farzati.Scott]

I just did a ring that was segmented.  The original print was drawn in the 60's by hand.  Not sure if it was standard practice to draw arc lengths back then?  But thats what I was given and I was looking to redraw it using degrees for a C-axis indexer.  Would've been nice to just draw in Fusion 2D with the length of arcs and then redimension to the angle off center line.

[HughesTooling]

How many of AutoCAD's features are parametric and can drive the sketch though? Inventor uses a third party library for it's sketch solver and I expect AutoCAD uses it as well, the one in Fusion written by AutoDesk. Fusion's sketch solver needs improving in speed and features but if it was easy they'd have done it and used it in Inventor and AutoCAD rather than pay Siemens. 

Mark

[g-andresen]

Hi Mark,

1. I don´t see any need for setting stretched lengths.
2. But I need the dimensioning function for sheet lengths in 2D drawings.                                                                                                                                                                                                                                

It´s important being able to detect points on the curve for measuring part lenghts.

 

I used this function in Ashlar Vellum-Cobalt.

Currently I use the measure tool as workaround.

Unfortunately this only works if the curve does not contain more than one segment.

many thanks for your effort

günther

[HughesTooling]

Hi günther

Yes I agree it's needed for 2d documentation, just wondered if any programs allowed fixed length splines in a parametric sketch. Could be useful for modeling hoses, ropes, etc. but would be interesting how edits to a point would affect the spline shape.

Mark

[Anonymous]

Yes, You can create and define arc lengths in Creo and use them as driving diemensions. The lack of this is a real problem for creating real world designs 😞

[TheCADWhisperer]

...and you can create Driving or Driven Arc Length dimensions in Autodesk Inventor Professional and use them in other parametric equations.

That is how I controlled this animation... 

Sorry about the dead time at the beginning of video - but let it play.

[chrisplyler]

For a given radius and desired arc length, set things up like this:

Then you know the arc length, in this case, is 30mm.

[HughesTooling]

The only workaround in Fusion is to use parameters to calculate the arc length or drive the included angle of the arc to get the correct length. The lack of driving dimensions is a real problem though.

Mark

[TheCADWhisperer]

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@HughesTooling wrote:

The only workaround in Fusion...

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Yes, I used to do the same thing in Autodesk Inventor more than 10 yrs ago.

It is really convenient to have the functionality to directly dimension Arc Length and to use Driven Dimensions in equations.  And the functionality to Animate Parameters is something that SolidWorks cannot do (at least in 2019, I haven't had access to 2020 yet to check). Edit: But it is also possible to directly dimension Arc Length and use Driven Dimensions in equations.

[dronmo]

The link to parametrizing arc length is not working, can you please elaborate on how to do that? thanks

[TheCADWhisperer]

@dronmo 

See post #14.

If you can’t figure it out, then Attach your file here.

[dronmo]

Hi, thanks, yep that helped 🙂 thank you

[chrisplyler]

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@dronmo wrote:

Hi, thanks, yep that helped 🙂 thank you

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Oh good! It took me a good little while to noodle that silly formula out, because I'm mentally challenged. So I'm really glad it has helped somebody.