Patterns and constraints

[Anonymous]

Is it possible to create a pattern and create a contraints that will always attach to the last component in the pattern? I have ilogic code to tell Inventor how many components I want in the pattern but I wasnt sure if I was able to write a program or something that will Inventor to find a certain feature of the last component and create a certain constraint on that feature. Thanks in advance. 

[cwhetten]

Hi and welcome to the forum!

It might be possible, but the code could be pretty complex.  I think there are easier ways to do what you want.  I would instead constrain to the assembly origin (best) or at least to the first component in the pattern.  Then you can control the offset so that it follows the last component in the pattern, regardless of how many elements the pattern has.

If you have an example assembly, attach it here.  Or at least an image that shows what you are trying to do.  If I have a better idea of what you are trying to accomplish, I could work up a simple example that demonstrates what I suggested above.

Cameron Whetten
Inventor 2014

[Anonymous]

Attached is a really bad drawing of what I am attempting to do but I am trying to create an assembly using the chevrons and dots. I made an ilogic rule to calculate the number of dots that I'll need to make a perfect arc around the edge of the chevron. The first dot in the first arc begins at the green line. From there, inventor removes the unnecessary dots that are not needed to make the arc, I wwant to make an ilicc rule to caluclate the distance bewteen the red lines then have inventor use the caluclated value to create a pattern of dots that extends from the red line on the left to the red line on the right. I want to move the second arc on the right varying distances from the center of the pattern while always keeping it between the chevrons.

  

[cwhetten]

So, to make sure I understand, your original question was about how to constrain the second arc so that it will always be in the correct place after the quantity of dots changes on the pattern between the red lines?

This shouldn't be too difficult.  It seems like you could do this with a parameter formula easily enough.  You would just need parameters for the location of the final dot before the first red line, and the quantity and spacing of the pattern between the red lines.  Depending on where your assembly origin is, you may need additional parameters for the location, quantity, and spacing of the initial arc.

Does this sound like it might work for you?

Cameron Whetten
Inventor 2014

[Anonymous]

Yes but it is easier said than done...I tried doing exactly what you said a couple times but I can't quite get it.

[cwhetten]

Can you post what you have so far?  Anything you can provide of what you have done so far would really help me to help you.

It would be a waste of your time to tell you to try things that you have already tried.

Cameron Whetten
Inventor 2014

[Anonymous]

Well both arcs have to clear the parallelagrams in the chevron pattern. I made a program using VBA in excel to calculate the number of dots needed to create an arc based on an angle that a user would input. The max angle between the dots is 4 degrees. So the program take the angle submitted and divides it by the number of dots needed to make the arc. Is there a way to maybe contrain the arc of dots to be parallel to a circle that I sketch on the edge of the parallelagram?

I tried constraining the end of the arc on the right where the red line is to the center line of the chevron. Then I attempted to create an algorithm that would calculate the distance from the center of the chevron patter to where the patter is. I dont think I am explaining what I am aiming for here very well...