topic Re: Arranging a hexagonal assembly element in a circular pattern in Inventor Forum

Arranging a hexagonal assembly element in a circular pattern

richter2felix — Fri, 17 Apr 2020 01:40:15 GMT

Hello,

I want to arrange hexagonal elements in a circular shape, like this:

The hexagonal element looks like this:

I tried using Pattern (in the combine section), circular, but the elements are placed into each other.

I really don't want to do it manually, because its about 1500 elements.

I hope this is an easy fix!

Thanks in advance!

Re: Arranging a hexagonal assembly element in a circular pattern

JDMather — Fri, 17 Apr 2020 11:58:56 GMT

I was just about to take the time to create an example to show you how to solve this - and then I realized that you didn't even state what version of Inventor you are using.

Are you using Inventor 2021?

Re: Arranging a hexagonal assembly element in a circular pattern

richter2felix — Fri, 17 Apr 2020 12:04:17 GMT

Thanks for your answer.

I am using Inventor 2019. With the students license, if that matters.

Best greetings

Re: Arranging a hexagonal assembly element in a circular pattern

JDMather — Fri, 17 Apr 2020 12:29:42 GMT

@richter2felix wrote:

I am using Inventor 2019. With the students license, if that matters.

What are you trying to model?

Do you have an image of the real world object?

Is it an assembly or is it a single part?

Re: Arranging a hexagonal assembly element in a circular pattern

richter2felix — Fri, 17 Apr 2020 12:38:06 GMT

I am writing an essay about Nuclear Thermal Propulsion.

This type of rocket contains a nuclear reactor with a core arranged out of long, hexagonal fuel elements. (see picture in the fist post).

The element is an assembly. (Fuel element + Coating on the axial surfaces)

The picture above is an excerpt of the fuel element arrangement, the full assembly contains about 1500 of these hexagonal elements.

The elements with the circurlar "interior" are support elements, that I do not need to include.

I hope this answer is sufficient.

Re: Arranging a hexagonal assembly element in a circular pattern

mcgyvr — Fri, 17 Apr 2020 12:46:07 GMT

Inventor really doesn't have a great way to do that type of operation (fill patterning).

You could use a sketch driven pattern which will take a bit of time to get the sketch setup like that but certainly doable.

Or you can look into using this code

https://modthemachine.typepad.com/my_weblog/2013/03/control-feature-creation-based-on-user-defined-boundary.html

Your pattern would really be a rectangular pattern not circular.. Its inside of a circular boundary but its a rectangular pattern..

Re: Arranging a hexagonal assembly element in a circular pattern

richter2felix — Fri, 17 Apr 2020 14:45:05 GMT

I hoped to just arrange 6 elements around an origin element with an 60° angle.

Next step 12 with a 30° and so on. Doing so would lead to an near circular arrangement, would'nt it?

And i guessed the Pattern (Circular) tool could do just that, but apparently it can't?!

@mcgyvr Thanks for your comment. Doing it as a sketch, would take a lot of time and I really do not want to invest that amount of effort. (Since it is just for visualization purposes in my thesis)

Your other suggestion looks a little overkill to me. I have not worked with algorithms or for that matter coded anything, in the context of Inventor, so I also would have to invest a lot of time into that.

Re: Arranging a hexagonal assembly element in a circular pattern

johnsonshiue — Fri, 17 Apr 2020 22:10:31 GMT

Hi! There should be a way to do that with some modeling steps. You don't have to constraint 1500 rods individually. I will share solution later.

Many thanks!

Re: Arranging a hexagonal assembly element in a circular pattern

johnsonshiue — Fri, 17 Apr 2020 23:24:01 GMT

Hi! Here you go! A 10-minute attempt on 2019. It is highly doable using Sketch-Driven Pattern.

Many thanks!

Re: Arranging a hexagonal assembly element in a circular pattern

Tom_Sturtevant — Sat, 18 Apr 2020 01:19:22 GMT

Hi –

I think a “honeycomb” like this is easier to model as a rectangular pattern starting with two hex cells at one corner.

I have attached a 2019 example which uses a sketch pattern of sketch point, and a sketch-based feature pattern based on that sketch. I did need to manually convert sketch points that fall outside of the circle from center points ( + ) to standard points ( . ) so the feature pattern would ignore them. Since you are really doing a one-off this is not too much effort.

The hardest part was positioning the two points at the lower-left corner to start the pattern.

If you will be using an Assembly pattern, you can make the part level Feature pattern a pattern of Work Points, then create the Assembly pattern associative with the Feature pattern. (So, Assembly pattern is based on the Part Feature pattern which is based on the Sketch pattern!).

Hope it helps!

T.0.M.

Re: Arranging a hexagonal assembly element in a circular pattern

richter2felix — Sat, 18 Apr 2020 14:22:45 GMT

First of all thank you both for your help!

I will look into your examples shortly!

@johnsonshiue Greetings from Bremen, Germany 😉

Re: Arranging a hexagonal assembly element in a circular pattern

Tom_Sturtevant — Sat, 18 Apr 2020 14:39:22 GMT

Elegant solution @johnsonshiue! It's going to take me more than "10 minutes" to figure out how you replicated the center points in the sketch...

Re: Arranging a hexagonal assembly element in a circular pattern

johnsonshiue — Sat, 18 Apr 2020 15:56:46 GMT

Hi @richter2felix,

Nice to meet with someone from Bremen! It is a very pretty town with a lot of history and interesting attractions. Highly recommended! I will revisit someday.

Let me explain how I approached the design. Inventor does not have the ability to do "Filled Pattern" (packing pattern instances within a boundary). Even if it did, "Filled Pattern" would not yield the predictable result like you wanted.

First of all, there is no way you can create the pattern using one patterning operation (circular or rectangular). It is just impossible without having overlapped instances. That leaves the choice to Sketch-Driven Pattern.

Then the focus becomes how to create the points to drive the pattern. Based on the image, there are two groups of points. Group A: the individual points evenly distributed around layers of hexagon boundary. Group B: the 6 outliers.

Next, you need to figure out the spacing between layers in Group A. Essentially, they are on one side of a hexagon (1/6). Add those points and constrain them accordingly. However, you cannot just pattern the points (on one side) together 6 times around the center. You will end up with points on top of points along the diagonals. To avoid that, you further break up Group A into two subgroups: A1) points on diagonals and A2) points not on diagonals. For A1 points, circular pattern 3 instances. For A2 points, circular pattern 6 instances.

Group B is the most straightforward one. You simply circular pattern 6 instances around the center.

Lastly, create a workpoint at the center. And, create a Sketch Driven Pattern (SDP) of the workpoint based on the sketch points. Place this skeletal part in an assembly. Insert a hexagon rod part at the center. Pattern Component based on the SDP.

BTW, the holes in the hexagon rod are populated similarly.

Many thanks!

Re: Arranging a hexagonal assembly element in a circular pattern

JDMather — Sat, 18 Apr 2020 19:44:00 GMT

@richter2felix

Here is my contribution...