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Hi all, I have foam board and I have made some buildings in the past but there all square. I need some help in figuring out how to work out the angles for angled walls and the joins. For example I want to make a bunker that is hexagonal in shape with a wider base than the roof. The walls would be inclined but I don’t know the mathematical side to work out the correct angles to cut.

I hope you lot can help,

Thanks

Well in your example I'd look up the internal angles of a hexagon which are 120°.

If we consider a clock with two hands, if the hands were pointing in opposite directions they would be at 180° from one another.

So if we need 120° we either change the angle of one hand by 60° or two hands by 30°.

So I'd cut the faces of your walls to 30° from square to get a hexagonal bunker

Ok that’s brilliant way of putting it, thanks

However what about the incline from the ground to the top?

http://www.quantumgothicwars.com/tabletop-gaming-scenery?product_id=74

That is an idea of what I want but the lower wall section is what’s causing me trouble

You can look these things up pretty good on the net but here is something quick:
The easiest way to figure out the angles of a symetrical shape is: 360 degrees divided by the number of sides and subtract the result from 180 degrees (corner angle = 180-(360/N)

Equilateral Triangle = 60 deg
Pentagon (5 sides) = 108 deg
Hexagon (6 sides) = 120 deg
Octogon (8 sides) = 135 deg
Decagon (10 sides) = 144 deg

You can then imagine how you would like your bunker to look if you take any of these shapes and flatten them out by cutting a section off from corner to corner.
A "Quonset hut" for instance would look good if you cut a Decagon in half.
A solid looking bunker would look good as an Octagon with the bottom 3 sides removed (vertical sides, 135 deg slopes, flat roof)

Hope that helps. I never gave that much thought before so it was a good exercise!

Ah, you posted more while I wrote this.

The bunker you show there, ah a "compound miter".
This calculator should work for you:
https://www.blocklayer.com/compoundmitereng.aspx

Assume the sloped walls on the bunker are 1/4" thick.
It looks like it is an Octagon so sides = 8
I would hazard a guess the slope is = 60 deg.

Play with it a bit and it starts making sense, the other long method involves "tan" ... I can explain further if needed but this tool "should" work.

That’s brilliant thanks, I think that tool is going to be very useful