calculating distance using rectangle pattern

[paulcasaqua]

When using the rectangular tool how do i calculate equal distances between each Fin.The picture shows 11 Fins but they are not equal distances between each Fin which causes the Fins to be higher on the right side.Which formula / calculation do i need to use in Rectangle Tool to produce equal distances between each fin and therefore the 1st and 11th fin are in the same position on each side of the cylinder.Using Inventor 2012

Regards,

Paul

[nannerdw]

I'd make parameters for Chord_Length and Fin_Thickness.

When you pattern the extruded feature, set the last dropdown box to "Distance."  Then set the distance to Chord_Length-Fin_Thickness.

Or if you're patterning in the sketch environment (not recommended), you would use (Chord_Length-Fin_Thickness)/(Num_Fins-1)

[JDMather]

Something like this?

[paulcasaqua]

Hi Nannerdw

Thanks

I attached your example and it works

Paul

[paulcasaqua]

Hi JD

Yes that works good as well.

How did you achieve / measure the curve length at 117.000mm

Thanks

Paul

[JDMather · Accepted solution]

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@paulcasaqua wrote:

Hi JD

How did you achieve / measure the curve length at 117.000mm

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I didn't.  I let Inventor do the work.

The other solution presented looked like too much work to me.  I am lazy, I try to avoid work.
Edit the feature and expand the Pattern Feature dialog box completely.  Examine the settings.

Also examine Sketch2 and click on the line that I added to highlight it.
You will notice that one end goes the midpoint of your rectangle and the midpoint of that line is also constrained to the vertical line.  That gives the distance that Inventor Measures as Curve Length in Pattern.
All geometry solution - no calculations. I avoid calculations to the extreem when I can find a geometric solution.

[paulcasaqua]

Thanks JD

Yes simple and easy but very effective

Paul

[JDMather]

This problem comes up here every year about this time.  Is it a school assignment?

[paulcasaqua]

JD

Not a school project.Self educating

Cheers

Paul

[paulcasaqua]

The attached example is again using Rectangle Pattern tool.This time i want the pattern to go along a straight edge with same distance between the holes.I used the Curve Pattern and the result gave same distance between each hole.Can using Spacing and Distance also give the same result as the Curve Length?

Paul

[JDMather]

Spacing - you put the the desired relative distance between instances.

Distance - you enter the total distance and Inventor calculates the spacing between instances.

What you use all depends on design intent.
One advantage to Curve Length is it is geometry driven - if you change the model the features will adapt to the change.
This might also be wrong behavior depending on your design intent.

Where Curve Length spacing really becomes powerful is in curved (not straight line) driven patterns.

The Rectangular Pattern tool in really a mis-nomer where it should have probably been called the "Curve Driven Feature Pattern - Where Often the Pattern is Linear" tool, but I guess that name would have been too long.

Have you seen examples of curve driven patterns?

http://home.pct.edu/~jmather/skillsusa%20university.pdf

[paulcasaqua]

Thanks JD

Thanks also for the PDF file

Paul

[JDMather]

The curve driven patterns are on pgs 16-18.