Editing length of segments on polygons

[WarrenGlass]

I have several polygons with a different number of sides. How do I edit the length of segments so each polygon segments are the same length?

[BillieRuben]

Do you have some screenshots of what you are trying to achieve? I could suggest various ways, but it will depend on their geometry.

[WarrenGlass]

These polygons will be attached each other to make a sphere. Each segment needs to be exactly the same length for good results. This is just a test size. The sphere will be a 14" diameter. Hope this helps.

[berainlb (PY)]

2 approaches:

1. Use Arrange->2-point rotate/scale to scale all shapes to a reference shape
2. Use the Shape Measurement tool to measure the length of the reference segment and segment you want to scale. Then mathematically determine the scale difference and use the Numeric Edits scale transformation to adjust size.

[Marcus_Wakefield]

Ok, give the attached a try.

I actually did this in Coreldraw then imported it into LB but there are a number of ways it can be done. Obviously make as many copies of each shape you need and when you come to scale just make sure you scale everything by the same factor!

Regular polygons with common side length.lbrn2 (9.6 KB)

[Marcus_Wakefield]

Here’s a better way…

Regular polygons with common side length.lbrn2 (155.7 KB)

Hope this helps.

[WarrenGlass]

First, Thank you and Berainlb for responses!! Second how did you and how would I figure the scaling factors?

[Marcus_Wakefield]

I knocked up a quick spreadsheet to calculate the potential scaling factors. I didn’t know initially whether it would be useful but it was. It just uses a bit of simple trig to calculate the circumscribing circle sizes for each shape to give a constant side length and from this calculate the scaling factors.

I’ve attached the spreadsheet but you’ll need to remove the .txt file extension (this is only added to get around the restrictions on the forum).

Hope it makes sense.
Regular polygon calculator.xlsx.txt (10.2 KB)

[berainlb (PY)]

I’ll offer a different approach:

1. Measure side of reference polygon. Take note. Ex. 100
2. Measure side of polygon to be scaled. Take note. Ex 80
3. Divide reference size by second size. 100/80 = 1.25
4. Select polygon to be scaled
5. In Numeric Edits field, set scale to 125% (1.25)

Again, I’d also encourage you to look into the 2-point rotate/scale as you can do this purely through on-screen manipulation.

More information here:
Two-Point Rotate - LightBurn Software Documentation

[WarrenGlass]

Thank you. I am trying out each way suggested and pick the one I can keep using on the many yet to be designed.

[WarrenGlass]

Thank you, Marcus. With your calculations I better understand why this project is not as straight forward as I thought before I started.

[berainlb (PY)]

Take a look at this post that includes a visual representation of how the 2-point rotate/scale functions. It should make this activity relatively trivial.

Is it possible to resize an object setting a segment length?

I realized it’s hard to see what’s happening if both lines are perfectly horizontal. Here’s an example with the reference segment rotated. [rotate-scale]

[Marcus_Wakefield]

@berainlb

I’ll offer a different approach:

1. Measure side of reference polygon. Take note. Ex. 100
2. Measure side of polygon to be scaled. Take note. Ex 80
3. Divide reference size by second size. 100/80 = 1.25
4. Select polygon to be scaled
5. In Numeric Edits field, set scale to 125% (1.25)

That’s exactly how I’d usually go about something like this, it’s quick and simple. I was interested however in how LB determines the size of the polygon when you change the number of sides, hence I created the spreadsheet, just for my own interest really.

[berainlb (PY)]

@Marcus_Wakefield

I was interested however in how LB determines the size of the polygon when you change the number of sides

A valuable exercise for sure as it’s somewhat unintuitive and a source of confusion for many.