Monday, October 1, 2018

Drawing to Scale & Basic Proportions 18-19 S1

Today we will be working on Drawing To Scale and Basic Proportions as an introduction to Architectural Design.  Please take a few moments to learn about this by watching the following videos:














BASIC PROPORTIONS (http://www.basic-mathematics.com/scale-drawings.html)
Since it is not always possible to draw on paper the actual size of real-life objects such as the real size of a car, an airplane, we need scale drawings to represent the size like the one you see below of a van.

Van image


In real-life, the length of this van may measure 240 inches. However, the length of a copy or print paper that you could use to draw this van is a little bit less than 12 inches

Since 240/12 = 20, you will need about 20 sheets of copy paper to draw the length of the actual size of the van

In order to use just one sheet, you could then use 1 inch on your drawing to represent 20 inches on the real-life object

You can write this situation as 1:20 or 1/20 or 1 to 20

Notice that the first number always refers to the length of the drawing on paper and the second number refers to the length of real-life object

Example #1:

Suppose a problem tells you that the length of a vehicle is drawn to scale. The scale of the drawing is 1:20

If the length of the drawing of the vehicle on paper is 12 inches, how long is the vehicle in real life?

Set up a proportion that will look like this:



Do a cross product by multiplying the numerator of one fraction by the denominator of the other fraction

We get :

Length of drawing × 20 = Real length × 1

Since length of drawing = 12, we get:

12 × 20 = Real length × 1

240 inches = Real length


Example #2:

The scale drawing of this tree is 1:500

If the height of the tree on paper is 20 inches, what is the height of the tree in real life?



Set up a proportion like this:


Do a cross product by multiplying the numerator of one fraction by the denominator of the other fraction

We get :

Height of drawing × 500 = Real height × 1

Since height of drawing = 20, we get:

20 × 500 = Real length × 1

10000 inches = Real height

DRAWING TO SCALE (http://www.probuildersslo.com/scale)
The whole idea behind creating a scale drawing is to keep the objects in the drawing proportionately accurate in relation to each other. By using a measuring device called a scale you can create accurate drawings of very large objects on a standard size piece of paper.

Scales Used to Create a Design Drawings
1:4 Scale pronounced: "One Quarter Scale" or One Quarter aSize.
1/4 inch on the scale = 1 unit on the object being drawn.


By extension, if we use 1/4“ graph paper, one 1/4” block can equal one inch, one foot, one mile, one light year etc. For architecture, 1/4“ usually equals 1’ (1/4 inch = 1 foot). Scaling is really up to you but be consistent with all measurements and dimensions otherwise the end result will be useless. Always note what the scale you used on the drawing and whenever possible use industry standard scales.

Engineering and Architectural Scales (in this case the word scale is being used as a noun referring to a type of measuring device) are made in a triangular form so that they can be marked with different scale ratios for versatility. Typically, a triangular scale has 12 different ratios on it - 6 on each end and related ones (like 1/4 and 1/8 for instance) interlace in opposite directions without interfering with each other. Below is what an Architectural Scale looks like.

How to Use Them
The scales on the Architectural Scale (isn’t it nice the way they make explaining this so easy:) are all related to measurements in feet and inches. Above is a representation of 1/4 scale. One quarter inch equals one foot. Notice that at the beginning of the scale the first 1/4” is divided into 12 subdivisions, one for each inch in a foot. Notice also that the ”0“ point starts after the initial smaller subdivisions. Watch out for that. If you don’t remember that the zero mark is not at the beginning of the scale you will end up with an inaccurate drawing. It is set up that way to make it easy to layout feet and inches - like 4’ 6”. The 4’ would use the main part of the scale and the 6“ would use half of the inches designation on the end. That makes laying out a drawing very easy. By using 1/4” graph paper you will greatly reduce your drawing time. The Architectural Scale will help you with the inch measurements on your design drawing.

For initial design layouts, accuracy to 1 inch is good enough. The contractor and cabinet maker will measure much more accurately, of course, but for your design drawing one inch is usually just fine.

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