Another type of annotation you might come across is NTS or not to scale. Avoid using NTS unless you are including a sketch or a something like a key plan which is just a reference for the actual detail to be read form the drawing. Producing a detail drawing with a Not To Scale tag is a serious No-No. I have seen people being asked to reprint because Key plan did not have a scale mentioned.

Most of the project drawings are usually in a scale where the drawing is smaller than the real life dimensions. Still there are situations and details which have to be blown up or drawn at a bigger scale to achieve better understanding of the situation. These can be seen in some fabrication drawings or joint details. Say you want to blow up a detail to twice its size. the scale in that case becomes 2:1 which means paper dimension is 2 times the actual dimension.

If real life dimension is 1m then how much will it be on paper?

If maths is not your forte and the last line bounced over your head the note box below should be of help.

For example in the image you see that scale for the Cabin floor plan is mentioned as 1:100. (This is a part of a preliminary plan for another project I am working on.) This scale means every cm on this sheet corresponds to a meter in real life thus the scale 1:100.

Scale is a simple case of Honey I shrunk the kids. Written in a ratio or fractions they denote how smaller or bigger the actual object is from the drawing or illustration in your hand. This definition is all you need to understand what the scale on the drawing means. Do remember when a actual object is scaled up or down proportions remain unchanged and vice versa.

Proportion

Size of elements which form a whole

You might hear some artists or architects lament on poor proportions of a sketch or talk about how breaking usual proportion creates a awe inspiring structure. Many monumental structures around the world are best objects to study the play of proportions. Proportions are relative size of one object to another to make a whole.

For example a huge room to the tune of 20 m X 20m will feel too small and cramped with a 3m high ceiling though this is the usual ceiling height and in many cases heights are well below this. Imaging a ballroom with the same height as your study. Here the proportions of length width and height combine together to create a ball room which would have felt like a cramped space.

Proportions might not be of much help when you just want to read architecture drawings but they help you understand the inherent design in those drawings.

Scale and proportions have played a big part in defining how we perceive building and other structure. In most of the ancient monuments the main entry steps were not always to a human scale instead they were in a monumental scale thus in perfect proportion with the building which they are a part of. A separate set of steps usually designed by dividing part of the bigger ones were used by people to go up and down. This creates a feeling of awe when someone approaches the building but when these buildings were to be appreciated from afar the proportions were on the mark thus creating a perfect balance.

While drawing architecture details remember every element on the detail should be in the same scale you cannot draw wall at a scale of 1:100 and then put a window at 1:50. This would not only disturb the proportions but will not reflect actual scenario.

Reading and Scaling Drawings

Most maps show a graphic scale which allows the map reader to measure distance and get an accurate idea of the on ground condition. The reason for this practice is to keep masurements accurat as the media on which the map is printed is expectedto shrink or expand uniformally. As these maps were used by sailors and travelers a shrunk paper without graphic scale would result in them getting lost.

Notice the varying graphical scale at the right corner of this Google Maps screenshot. Click to enlarge the image.

Most architecture drawings on the other hand specify scale and pointedly discourage measuring the drawing to arrive at any dimension. There might be instances where drafting is erroneous but the dimension specified is correct or the dimension has been corrected after printing but is not correct graphically. These correction are sometimes necessary thus if drawings are measured design intent is not carried through and final result will be far different than what an architect wants.

Annotations become very important and care should be taken to make sure no required dimensions are missing or duplicate dimensions are not there.

Here’s a quick quiz to check if you understood how to scale an object and what will the drawn dimension be.

1. One edge of the cube measures 6m. How much will it be if you have to draw it at a scale of: