topic Re: spline and helix length to parameter in Inventor Forum

spline and helix length to parameter

cadman777 — Tue, 01 Nov 2022 00:15:56 GMT

Hi all...

Does anyone know how to automatically get the length of a spline and helix segment and attach it to a Parameter so if the geometry changes the Parameter updates?

I'd be grateful for any input on this.

Re: spline and helix length to parameter

Gabriel_Watson — Tue, 01 Nov 2022 02:41:36 GMT

Probably should post this in the iLogic forum. I think you can measure the length of the feature then save it as a parameter later.

Similar threads:
https://forums.autodesk.com/t5/inventor-forum/how-to-use-ilogic-to-measure-length-of-edge/td-p/10542177
And here:
https://www.cadforum.cz/en/ilogic-rule-to-measure-loop-length-in-a-sketch-tip8910

Re: spline and helix length to parameter

cadman777 — Tue, 01 Nov 2022 19:22:03 GMT

Thanx for that info. Unfortunately I had already went down that pathway and found no solution. I was hoping Sergio's iLogic code would work, but I kept getting an error that I could not figure out. The other caveat is, I want to measure the geometry not the feature. Do you know if that is possible?

Incidentally, the Measure tool works just fine, so there must be a way to do it using iLogic or VBA, right?

The way I envision doing it is to first identify the sketch and then the geometric entity by type that's inside that sketch. Then solicit the measure command and apply it to that entity. Then input that value into a UserParameter. Done.

But maybe I'll be forced to make the feature a sweep and measure that?

Thanx for the links, they may lead to something else that works.

Re: spline and helix length to parameter

blandb — Tue, 01 Nov 2022 20:47:44 GMT

Does this sound like something you are looking for?

https://www.youtube.com/watch?v=2mpzme_GGBA

Re: spline and helix length to parameter

johnsonshiue — Wed, 02 Nov 2022 00:57:12 GMT

Hi Chris,

Maybe this thread could help.

https://forums.autodesk.com/t5/inventor-ilogic-and-vb-net-forum/measure-the-length-of-3d-sketch-helix-spiral/td-p/9532112

Many thanks!

Re: spline and helix length to parameter

cadman777 — Wed, 02 Nov 2022 19:41:24 GMT

@Gabriel_Watson: Thanx for your help! Unfortunately none of those worked (IV2010).

@blandb: Before coming in here I stumbled across Mark's blog. Unfortunately, all the pics and code were missing on the blog (broken links). However, the video was very informative. So I took the time to manually type-in the code and test it. Unfortunately it didn't work. Bummer! Anyway, thanx for your input!

@johnsonshiue: Thanx for that link! It just goes to show how bad my memory is these days! I asked this question back in 2019, and discovered that it was impossible to do in IV2010. So I'm repeating what I did back then: manually measuring the curve and manually inputting it into the Parameter. That's the only manual work I have to do on this project, so I'm OK with it.

Cheers!

Re: spline and helix length to parameter

johnsonshiue — Thu, 03 Nov 2022 20:08:10 GMT

Hi Chris,

You are more than welcome! When I found the thread, I thought you might have seen it. I just wanted to share it with other users. My memory also suffers occasional corruption. The Covid isolation did not help.

I wish you could upgrade to more recent releases. Your request can be fulfilled by an iLogic rule relatively easily.

Many thanks!

Re: spline and helix length to parameter

cadman777 — Thu, 03 Nov 2022 12:42:14 GMT

I hear ya. I too wish I could upgrade. Unfortunately, I can't afford it. Besides, I don't believe in slavery.

Based on the world politics that I know, software subscription is a white collar version of slavery and extortion (as I've said in other threads). The fact that everyone has grown accustomed to that kind of criminal activity and accepts it without a peep is something I can't comprehend. Where are all the MEN today?

Software subscription is basically the legitimization of the corporate mafia. Sad the world we live in today. There's a verse in the Bible that says when Jesus returns to rule the planet, all the rich will serve him (12:1, p114). That's quite a change, considering how today the 'idle rich' are screwing everyone in the world through their fiat money based monopoly capitalism and their monopoly on labor through corporate social structure. Unfortunately for them, they will pay for their evil deeds on Judgment Day.

Thanx again for your constant excellent input!

Re: spline and helix length to parameter

cadman777 — Thu, 03 Nov 2022 23:45:45 GMT

I guess it's time to go back to basics...as usual!

Here's how I did it for the HELIX.

I guess the developers wanted us to do our own math.

I constructed the Helix using Revs & Height, but you can do it with Pitch & Height as well.

Took a little doing, b/c first I had to make Parameters for height of 1 full Rev and # of Revs in the total height.

The rest was easy.

Re: spline and helix length to parameter

b.mccarthy — Sat, 21 Jan 2023 20:55:10 GMT

Ladies & Gents...

I opened the unmodified Helix_Length-01.ipt and checked the G_L_Helix parameter:

I checked this against the result from the Measure tool.:

Except for the precision setting, these seem to match. Notice the metric value.

I then ran the unmodified 3D loop length rule as defined in @Gabriel_Watson's post above (Message 2):

https://www.cadforum.cz/en/ilogic-rule-to-measure-loop-length-in-a-sketch-tip8910 and this displays:

Not sure why this is different. Can anyone verify this?

Thank you.

Re: spline and helix length to parameter

johnsonshiue — Mon, 23 Jan 2023 21:49:02 GMT

Hi! The cadforum's iLogic rule is for measuring 3D lines, not for 3D splines or helical curves. Here is a simple rule I found to show the helical curve length in mm. There is still minor discrepancy between the shown value and the measured result.

Dim oDoc As PartDocument = ThisDoc.Document
Dim Sketch As Sketch3D
Sketch = oDoc.ComponentDefinition.Sketches3D(1)
Dim SE As SketchFixedSplines3D
SE = Sketch.SketchFixedSplines3D
MsgBox(SE.Item(1).Length*10)

I need to work with the project team to understand it better.

Many thanks!

Re: spline and helix length to parameter

MjDeck — Mon, 23 Jan 2023 23:11:54 GMT

Hi Johnson,
The Length value from the SketchFixedSpline3D object is close, but it is not as accurate as what you get from the Measure command.
You can use the MeasureTools API to get a more accurate number:

Dim oDoc As PartDocument = ThisDoc.Document Dim sketch1 As Sketch3D sketch1 = oDoc.ComponentDefinition.Sketches3D(1) Dim splines3d As SketchFixedSplines3D splines3d = sketch1.SketchFixedSplines3D Dim lengthInInches As Double lengthInInches = ThisApplication.MeasureTools.GetLoopLength(splines3d.Item(1)) / 2.54 MessageBox.Show("Length in inches = " & lengthInInches, "Measure Length")