An old room with weird corners

[Shadowfirebird]

I'm trying to create a plan for an old room in which the corners are not at 90 degrees.

I had hoped that I could just enter the wall lengths and then drag them around until the room was right in the program - but when you drag a wall it changes the length, so that doesn't work.

Has anyone got any ideas on how I can measure the angles of my room so that I can enter them in the program?

Or, a way of using the program so that I don't have to measure the angles?

[hansmex]

Shadow,

1 - Use a bevel protractor to directly measure the angle of your corners. You can make one yourself using a regular protractor and a ruler.
2 - Using paper or cardboard, make molds of every corner. Then use a protractor to measure the angle.
3 - Locate building plans and use them as a background image.

Hans

[Shadowfirebird]

That's brilliant, thanks! I'll see if I can buy or make a bevel protractor -- I see plenty of pictures on google.

As for the building plans, if I had some, I wouldn't need to use the program...

[Shadowfirebird]

That's interesting. I've just found the plans, not for the room as it is now, but for the modifications the last owners had planned.

Those plans contain neither corner angles nor dimensions.

[Shadowfirebird]

update: I bought something similar to this and while it works brilliantly for measuring outside angles, it fails at measuring inside angles like the corner of a room.

The problem is that you can't get it into the corner; one of the two "feet" on the protractor stops you. So, buy carefully.

[Shadowfirebird]

I had an inspiration. I think I may have a different solution, if you have a scientific calculator.

1) Measure the same distance out from the corner on both sides. Call that distance a.

2) now measure the distance between those two points. Call that distance b.

3) calculate (2a^2 - b^2) / 2a^2

4) push your cos^-1 button (arc-cos). The result should be the angle. I think.

[Puybaret]

Shadowfirebird, your idea is on the right track, but there's an easier formula.
From the following schema:



A sin([font=times new roman]α[/font]/2) = B/2
[font=times new roman]α[/font] = 2 arcsin(B/2A)

[Shadowfirebird]

Of course! Thank you!