 We have to distinguish between: › Artistic drawing  No rules  Express feelings and emotions › Technical drawing  International standards (rules)  Transmit ideas – Represent objects

 Aims of graphic expression in Technology: 1. To design objects or organise ideas 2. To show our ideas to other people 3. To make our designs attractive

 Pencil. They have a wooden case with a lead inside made of graphite and clay. +

 There are two types of pencil: H and B. › Hard pencils (H)  Thin lines  Technical drawing › Soft pencils (B)  Thick lines  Artistic drawing Intermediate

 Paper can be classified by size, weight and finish.  Depending on the size we differentiate different formats: › Starting with DIN-A0 (Deustche Industrienorm): 84.1 cm cm A5 A1 A2 A3 A4

 Depending on the weight the paper is thicker or thinner.  Depending on the finish we distinguish: › Rough paper › Smooth paper › Shiny paper

 Ruler. We use it to measure the length of a segment.  Protractor. We use it to measure and draw angles.

 Set square. For drawing parallel and perpendicular lines. They come in two shapes: › Right-angled isosceles triangle. › Right-angled scalene triangle

 Compasses. Two connected arms, one with a sharp metal point and the other with a lead. It is used to draw circles and arcs.

 Sketch. Freehand. Shows first idea of the object.  Diagram. Freehand. Gives more specific information: measurements, materials,…  Technical drawing: Same information as a diagram, but using drawing tools (ruler, set squares, compasses,… or a computer) SketchDiagramTechnical Drawing

1. Write these grades of pencils in order form the softest to the hardest: H, 3B, 5H, HB, 6B, 3H. 2. Match each word or phrase to the correct definition. 3. Draw your pencil sharpener to these scales: a) 1:1 b) 1:2 c) 2:1 Set square Ruler Compasses Protactor We use it to measure to measure angles We use it to draw parallel and perpendicular lines We use it to draw arcs and circumferences We use it to measure lines.

 Definition. We use the scales to fit the objects on the drawing surface (paper). There are 3 types of scales:  Full Scale. We draw the life-size object. (S = 1:1).  Scale to reduce. To draw objects bigger than the paper. (S = 1:X). Examples: S=1:2, S=1:10… Scale to reduce  Scale to enlarge. (S = X:1). Examples: S=2:1, S=5:1,… Scale to enlarge

 DIMENSIONS: SHOW THE REAL MEASUREMENTS OF AN OBJECT TO HELP US UNDERSTAND THE DRAWING.  Dimension rules › 1 st. Normally dimensions are expressed in milimeters. If not, we have to indicate the units. › 2 nd. Don’t duplicate the information (only draw the necessary dimensions). › 3 rd. Draw the dimension centered above the dimension line. If it is vertical, draw it on the left. › 4 th. Don’t use parts of the piece as auxiliary dimension lines. › 5 th. If possible, no line should cross any dimension line

 Created by projecting the points of a three-dimensional object onto a two- dimensional plane

 Orthographic projection consisting of systematically arranged views to describe an object

 Six normal views: › Front (alzado) › Back › Top (overhead)  plan › Bottom › Right side › Left side

 Height is how tall the object is, as measured on the front view  Width is how wide the object is, as measured on the front view  Depth is how deep the object is from front to back  Each dimension appears twice in the three regular views  “Length” and “breadth” are terms not used

 Perpendicular  Parallel  Inclined

 Edge view  True size and shape  Foreshortened shape

 Frontal plane  Horizontal plane  Profile plane

 Draw a side view and an overhead view of these objects.

 Js