Trouble with floor plans of rooms with odd angles.

[cantab]

My boss has asked me to draw up plans of one of our buildings. It's located on an acute corner, so the overall building's roughly V-shaped and inside there's scarcely a right angle around. Drawing the plans is giving me real trouble.

I'm working on mm graph paper at 1:50 scale, measuring to the nearest cm and drawing to the nearest mm on the page / 5 cm in the room.

I've tried measuring diagonals and using trig to get the angles, and I've tried measuring the angles of the walls directly using a folding rule to transfer them to the page, but either way I find that if I measure and draw all but one of the walls, the last one doesn't match up, usually with misalignments or length mismatches of about foot.

Other than just fudging it (which I could do because the plans are wanted to mark call points and so on for the fire safety people, not for any actual building work), what should I do to measure these rooms without getting this sort of error?

 

[rjm2k]

sounds like overkill, just draw a rough diagram eh unless you are trying to impress the boss?

Or use some software, put the external walls in at the right lengths and link them up, there should only be 1 way they can actually fit together.

 

[freddiemercurystwin]

You don't need any angles just the wall lengths and the diagonal lengths. Walls are often not straight which throws things out further.

Without proper surveying equipment there will always be inaccuracies. Even full blown surveys come with a tolerance.

Really though a fire plan doesn't really need to be super accurate. Drawing it at 1:50 by hand won't help either, download Sketchup and draw it in that for a cheapy easy accurate means of drawing it up if you want more accuracy.

 

[foxhole]

Don't you have plans of building, should be available.?

 

[cantab]

Impress myself, I think, more than the boss. I plan on doing the end result digitally of course, but I'm working to scale as I measure to spot errors like I've mentioned and because I tried just sketching things freehand at first and ended up with a horrible mess of scribbles. I worry, perhaps irrationally so, that a bunch of small errors will add up and I'll get a plan that bears no resemblance to reality. And building plans, I wish; there might be some somewhere, but God knows who knows where.

I'll bear in mind that the wall and diagonal lengths should be sufficient, thanks mercury.

 

[Harbourwoodwork]

the way to measure and re draw a complex shape , use boat building method called lofting,it is the use of datum lines establish one central datum line ,laser or string, at 90 d to that central line draw a series of lines at constant intervals these are called stations,station lines extend to the edges of the area to be copied the rest is easy, give the station lines numbers write a table of offsets scale as you please, job done .

 

[foxhole]

Yea, what harbourwoodwork said.

 

[freddiemercurystwin]

He's doin' a poxy fire plan!

 

[ntb]

If I was your boss, I'd be more impressed if you got it done quickly and then got on with something productive