That way only work if the Object is like an rectangle Alvin, a plot i veeery seldom that, and the same with diretion on a map.
And use one of the smallest room in a big houseplan will never give an accurate scale, it should be as big as possible,
The easiest way in my opinion for this kind of rectangular objects is just to meassure the length of room, 6 decimal, copy that number and divide what we know is distance with what we meassure, enter and we have the scalefactor to type in, we dont need to draw a rectangle.
And it's the decimal's that give us the most correct answer, so minimum 6, at least for my use
, and Don using 10, even better but then you guys work with 25,4 of my units so …
What i would have done after Don's example is to draw a polyline around it all, you also have cc system that are most likely used, adjust the different sides to fit inside a system and scale picture/ pdf one more time, this time by using squereroot and you get the most accurate possible based on Picture or pdf, and again, normally there is some info about total area of a houseplan, then it's just to do as i say on top here, adjust the lines and finish, as close it could be.
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