Set exact size of a polygon side?

[EJ Ciramella]

Hi all - 

I'm trying to set the exact size of a pentagon - and I'm struggling to figure this out.

I can see how to set a height and width, but that doesn't give me an explicit side length.

My ultimate goal is to create a template that I'll use to cut out some stainless steel and make a soccer ball.  This is something I'd just crank out in fusion and go over to the plasma table, but this seems like something I should be able to so easily in affinity designer 2, but it's not super apparent.

[Alfred]

Why not start with one of the sides? That’s just a straight line of whatever length you care to specify, and you can then duplicate it an rotate the duplicate by 72° (i.e. 360/5°) for each of the remaining four sides. Use the ‘Join’ button (displayed on the Context toolbar when the Node Tool is active) to join adjacent sides of the pentagon.

[Old Bruce]

What about the Hexagon lengths?

Soccer/Footballs are made of both 5 and 6 sided objects.

[Alfred]

42 minutes ago, Old Bruce said:

What about the Hexagon lengths?

The hexagon lengths should be the same as the pentagon lengths, shouldn’t they? You simply need to set the rotation angle to 60° instead of 72°.

[EJ Ciramella]

1 hour ago, Alfred said:

Why not start with one of the sides? That’s just a straight line of whatever length you care to specify, and you can then duplicate it an rotate the duplicate by 72° (i.e. 360/5°) for each of the remaining four sides. Use the ‘Join’ button (displayed on the Context toolbar when the Node Tool is active) to join adjacent sides of the pentagon.

Yep!  This is how I ended up solving it.  This vs. specifying the length of one side and asking for a hexagon:

 

[EJ Ciramella]

1 hour ago, Old Bruce said:

What about the Hexagon lengths?

Soccer/Footballs are made of both 5 and 6 sided objects.

Yep, but I have to start somewhere - some soccer balls are made of hexagon and pentagons (20 and 12 respectively), and I realize there are other shapes that make up other other styles of soccer balls as well.  

For soccer balls made of hexagons and pentagons, the sides are the same length of both.

[EJ Ciramella]

Just so we're clear - I'm just used to doing this a different way and trying to learn how to do it with the tool at hand.

It's 30 degrees here - I don't feel like putting water in the plasma table and going the Fusion 360 route.  I really wanted to Print out some templates and cut some aluminum or stainless with the jigsaw and tack it up quick.

Another way I found is just draw both shapes and specify height/with of the hexagon that you want.  Then, using the measure tool (I could only find it in Affinity Designer 2, so I upgraded), determine how big a given hexagon side is.  Then you can take that size and resize each side of the pentagon.

Neither way is as efficient as I've experienced in Fusion, but I'm holding out for someone who has a more efficient approach.

[firstdefence]

On a hexagon (6-sided) the side length is half the height so a 10cm x 10cm hexagon has 6 sides with a  side length of 5cm each. 

A pentagon (5-sided) is easy to set with this webpage: https://www.omnicalculator.com/math/pentagon

A few assumptions have been made. You have the transform panel in view, you have set the polygon tool to 5 sides, you know about cycling selection boxes, you know to double click in the transform input boxes, you have a good memory and you are wearing clean undies in case you have an accident. 

1. Type the Side (a) length you want and pay attention to the Height (h) measurement
2. In Affinity hold down Shift and drag out a pentagon. 
3. Press . (fullstop) on the keyboard, this cycles the selection box. (tightens it up)
4. On the transform panel type the Height (h) measurement into the H: input box and press enter

To test, measure a side.

 

 

[walt.farrell]

1 hour ago, EJ Ciramella said:

Then you can take that size and resize each side of the pentagon.

Perhaps:

1. Draw your polygon. If needed, rotate so you have one edge horizontal.
2. Draw a line over that horizontal edge, from corner to corner.
3. In the Transform panel, set the length of that line to your desired edge size for the polygon.
4. Select the polygon, and type . to set the tighter bounding box.
5. Hold Shift to constrain (if needed), grab the upper-right corner of the bounding box, and drag upward to resize the polygon. Stop when the bottom edge is as wide as the line. Note: This is probably a multi-step process, with occasional pauses to realign the polygon and the line for proper comparison.

[lepr]

4 hours ago, EJ Ciramella said:

I'm trying to set the exact size of a pentagon - and I'm struggling to figure this out.

I can see how to set a height and width, but that doesn't give me an explicit side length.

 

Point Transform Tool to the rescue.

Video shows example of setting hexagon and pentagon edges to 50 mm.