# How to set Circular Array Radius?

I want to create a circular LED array having 16 LEDs, evenly spaced. I am having some success with creating the array in a circular fashion with the 0/12, 3, 6, and 9 o’clock positions properly placed by setting the horizontal and vertical centers to 0.

I have read the directions and web posts, however I still do not understand how to set the radius. Please clue me in.

RE: Array Tools/Circular Arrays

Here’s a quick/simple way to achieve this.

1. Place your component at the origin (0, 0)
2. Select your component and start the circular array tool
3. Set the horizontal (or vertical but not both) center at the radius you want
4. Choose the angle and count
5. After creating the array, select and move the elements as a group.

Alternatively, here’s a video showing the offset method. Pick the position of the element and add your radius to the X value.

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Well, I think that I am doing the steps correctly?
Place your component at the origin (0, 0)
Placed the component near/at the grid origin and zeroed it out with the space bar, just to be sure.

Select your component and start the circular array tool
Moved the desired component from the existing population. Then, zeroed out, per above step.

Set the horizontal (or vertical but not both) center at the radius you want
I am looking for about a 2" diameter, so I set the radius to 25mm.

Choose the angle and count
Count is 16
Angle = 360/16

After creating the array, select and move the elements as a group.
Select okay and get a radius of 191mm?

What am I missing? Thank you!

Hmm… I was able to get it to work by…
Selecting an LED from the pooled existing population, without moving it.
Used its existing coordinates and added 25mm.
So, it does not seem to like to be moved and zeroed out.

Also tried it with the first LED that was moved near the origin. Used the non zeroed out perimeters and added 25mm. This did not really improve things.

Suggestions/thoughts?
Thanks!

I haven’t used the feature but by looking at the dialog I wouldn’t have an idea what to do. Here’s what I would expect:

• Selecting the center point, possibly in the same way than in Position Relative To dialog in pre-5.1 - use Local Origin, use Grid Origin, select item. Selecting an item would make possible for example drawing a graphic circle as a model.
• Location of the first item relative to the center point. Alternatively “use polar coordinates”: distance and angle of the first item.
• Angle between two items.
• Count.

One thing that contributes an error is that the origin of the LED_D5.0mm_Horizontal_O3.81mm_Z3.0mm is centered on a pin, not the body of the bulb. This offsets the center line of the opposing LED by the width of the spacing between the two pins. I will have to move the origin in the component editor.

Apparently, this center point is currently always defined by the grid origin, and the footprints are placed around it, while when you use the Grid Array tab (in the same dialog), the item anchor defines the origin of the array. It’s rather confusing.

On the other hand I don’t see how Grid and Circle could use same kind of origin. It’s impractical to define circle by using a point of its circumference and it would be impractical to set the origin of grid to something else than its first item. The downside of my own suggestion is that the first item (the selected one which is copied) would be moved when the circular array is created.

This speculation doesn’t help @td1, but I don’t understand his/her last message.

Does it work or not?

It sounds more practical to me to define the center of the circle relatively to a well / already placed item, rather than the grid origin which is often off-the board. But the best way is probably to have this choice (wishlist ?).

As to whether I have it working, or not…

Hmm… I was able to get it to work by…
Selecting an LED from the pooled existing population, without moving it.
Used its existing coordinates and added 25mm.
So, it does not seem to like to be moved and zeroed out.

Also tried it with the first LED that was moved near the origin. Used the non zeroed out perimeters and added 25mm. This did not really improve things.

These were two different methods. With the first, I was able to get a 2" circle. The second method gave failed results, similar to to the original failure. Therefore, “This did not really improve things.”

Bottom line, I have not found a method that reproduces the proper result consistently. I get cock-eyed LEDs in their proper positions around the circle. If I turn the rotation off, they all rotate to the same (wrong) orientation. The circle may build with all the LEDs pointing inward.

I am having difficulty understanding the relationship of the way the horizontal and vertical centers are related to the way the circle builds. However, I understand that adding the needed offset distance to one of the centers defines the circumference.

I am doing my best to follow the directions exactly, but I do not feel well and this is surely limiting my ability to think this through. Maybe if someone could go back through the directions and expound on each step I could find my error. It seems clear enough, but obviously I am missing something. Thank you for this extra help.

Using the vertical center… This is corrected by subtracting the needed circumference, instead of adding it. This also builds the circle above the subject component… Adding built the circle below the subject component.

Here is the progress I have made.
Basically, I just had to fiddle with it, until I understood how to get what I needed.
I look forward to arced traces in Version 6.