# Discussion Forum

## How to model a honeycomb matrix

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Hi!

I'm trying to model a honeycomb (HC) pattern by combining/mixing two identical matrixes into one (the HC).

Let's say that the "first" matrix is the reference and that the "second" matrix (copy/paste of the "first") will have a shift, aka displacement, in the x and y axis given by two variables (parameters) so that the two combined/mixed present the HC pattern.

I've build my substrate and a cylinder on its surface. I'm using that cylinder for the array in the x and y axis (being z = 1). This "first" matrix works like a charm. I change all the parameters of the cylinder, including the pitch between them, and it already appears to start wrongly since my initial coordinates (x0, y0, z0) and set to (0, 0, parameter) but the bottom left cylinder appears on coordinates (1, 1, 1) as explained in the next paragraph).

First, and for some reason, COMSOL does not let me choose the same cylinder as I have for the "first" matrix as input object for this "second" matrix (so that I'd have the exact same reference for both matrixes). I've tried by clicking said cylinder with the mouse, copy/pasting and naming it on the input objects window and nothing. So, because of that, I have to click on a cylinder (from the "first" matrix) which is on the same position as mentioned reference cylinder and I get as input object "arr4(1, 1, 1)".

Just as the first test the value I input as x displacement is a parameter dst_x (distance in the x axis) which is equal to the pitch + 2 * radius of the reference cylinder times sqrt(3)/2. And this new matrix (only one line on the x axis is actually changinging) is drawn in such a way that I do not understand (I should mention that all the units are the same).

The bottom left most cylinder of the "second" matrix is drawn on the exact same place as in the "first" matrix meaning that the bottom left most cylinder is also in coordinates (1, 1, 1) so, obviously, I will not have any actual x axis displacement between the 2 matrixes since the bottom left most cylinders are on the same x axis position therefore I will never have a HC pattern.

See pictures I've attached.

What's happening? I thought this would be the "simplest" way to model a HC pattern. I don't know if there's a "better" way to model it but if there's please advise on that.

Thanks!

Rui

2 Replies Last Post Apr 9, 2021, 5:40 AM EDT

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Posted: 1 week ago
Updated: 1 week ago

I'm having trouble figuring out what geometry you are trying to create. The pictures you posted seem to show circles in 2D arrangements, although you're talking about cylinders, and I'm not sure how a "substrate" is involved. By "honeycomb matrix," are you referring to a hexagonal-tiled layout of your circles? I'm guessing that, because bees make honeycomb in that kind of arrangement. Anyway, are you trying make something that looks (roughly) like the arrangement of circles in the figure that I've attached?

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Posted: 1 week ago
Updated: 1 week ago

Hi @Robert Koslover.

Thanks for the quick reply and I'm sorry I couldn't be clearer in my description but your image is exactly what I was trying to model!

In a one in a million shot yesterday I met a guy with experience in COMSOL and, apparently, what I had "just" to do (not very obvious in my opinion though) was to make a copy of my array (under model) that built my "first" matrix and then check the "Resulting objects selection" box instead of trying to make arrays based on a single reference cylinder (which by the way the circles you saw were just the top view of the cylinders).

So in this new copy of the matrix ("second" matrix) my input objects were all the elements from the "first" matrix (instead if just the reference cylinder) and it is here that I write the appropriate displacement in x and y.

I hope I was clear enough this time. :)

Best regards,

Rui

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