Extension material for Level 2 Design and Visual Communication Study Guide

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3-D formal drawing Extension material for Level 2 Design and Visual Communication Study Guide ISBN 978-1-927194-15-7 For individual student use only. No other use permitted.

1 3-D formal drawing Extension material for Level 2 Design and Visual Communication Study Guide ISBN For individual student use only. No other use permitted. ESA Publications (NZ) Ltd, D drawing basics NCEA Level 2 Design and Visual Communication does not require you to have an understanding to all pictorial drawing forms. It focuses on perspective drawing. Here are some other pictorial drawing systems that could help you explore and communicate design ideas to a wider audience. This weblet will provide you with an understanding of: oblique axonometric planometric exploded pictorial views. Pictorial drawings Plans and elevations show two dimensions they are flat. Pictorial drawings show three dimensions length, width and height. It is the third dimension that changes an elevation or plan into a pictorial view, making the object appear solid. Complex drawings can be built up by using crating. Remember angles cannot be transferred to isometric and measurements can only be transferred along axial lines, so it is sometimes necessary to draw elevations or plans to obtain measurements for plotting points before drawing in pictorial. Oblique The oblique view is probably the simplest of all pictorial methods, but has the disadvantage of distortion. However, it is ideal for drawing curved or circular surfaces. Start by drawing the most difficult shape as a flat view constructed in a frame and build up the drawing using crating techniques. Axonometric Axonometric is the base for pictorial drawing that includes isometric, trimetric and dimetric. These forms of pictorial provide an opportunity for students to experiment with presentation and highlighting specific views and emphasising a side. Fig. 1 gives a representation of the three drawing forms. The angles can be altered to give better views.

2 3-D formal drawing ISOMETRIC DIMETRIC TRIMETRIC Fig. 1: Axonometric views If you are using any of these in a portfolio, it is strongly recommended that the construction is left in and an alternative copy rendered. You should also identify which form of axonometric it is. Planometric Planometric is drawn from a true plan rotated to be at an angle, usually 45º/45º or 30º/60º. Vertical lines are drawn up from the corners of all features. Usually the height is scaled back to 75%, or the object will appear too high. Construction 1. To start an instrumental pictorial drawing, draw the crate that the object would fit snugly into. This must be in the chosen view (i.e. if the drawing is to be in oblique, the crate must be in oblique). Use a hard pencil (a 2H or 3H) and draw very light construction lines. Make the crate wire frame or see-through. 2. Start putting in the details, positioning points along the axes and joining where necessary. Do all this with very light construction lines, which may cross at the corners. 3. When the outline is decided on, use a darker line to complete the drawing. If the drawing is to be rendered, keep the outlines light until the light source and tonal values are set up.

Drawing curves in pictorial views To draw curves, an ordinate method is used. 3-D formal drawing 3 1. Draw the curved shape as a plan or elevation in a box. 2.

3 Drawing curves in pictorial views To draw curves, an ordinate method is used. 3-D formal drawing 3 1. Draw the curved shape as a plan or elevation in a box. 2. Draw a number of equally spaced vertical lines across the box. The more lines drawn, the more plotting points and the higher the accuracy. 3. On the pictorial view, draw the same number of vertical lines, using the same spacing. 4. Measure the length of each ordinate on the flat view and transfer to the pictorial view, by means of a compass or dividers. 5. Draw a smooth curve through the plotting points by using French curves or a flexible rule , 4 5. Fig. 2: Ordinate method of drawing curves Exploded pictorial drawings The ability to see inside an object in 2-D drawing is called a section. In 3-D drawing we produce an exploded view whereby the component parts are spread out but done so in a line that will allow the interaction to be seen. The images in Fig. 3 are basically the same but notice the detail of the line drawing. Fig. 3: Two types of exploded pictorial one rendered and one a line drawing

4 3-D formal drawing 4 Activity 1: 3-D drawing basics Direction of viewing H V Redraw this block in both oblique and isometric. Then draw some conclusions about the two drawing systems.

5 3-D formal drawing 5 3-D drawing isometric and scaled isometric NCEA Level 2 DVC material covered in this weblet includes the study of isometric and scaled isometric 3-D drawing by an understanding of: isometric isometric projection. If you intend to draw a scale isometric then it needs to be just that, 81/100th of full size. This can be achieved by using the method described below. Leaving construction is a good clue for the markers. Isometric In isometric, the height, width and length are shown as parallel sets of lines and can be drawn to the actual scale. One corner or edge remains closest to the viewer. All lines which are horizontal on the object are drawn at 30º to the horizontal. All vertical lines will remain as vertical lines on the drawing. Inclined lines may be drawn after their end points have been plotted along the isometric axes. Isometric projection Isometric projection differs from the isometric drawings described above in that it takes account of the foreshortening of the axes as seen when the form is tilted. When a cube is tilted and viewed with a corner closest to the viewer all the edges appear shorter as they are no longer vertical. However, when a sphere is tilted and viewed it appears the same. So if a sphere and another geometric form appear in the same isometric drawing they will look wrong together unless the form is drawn to an isometric scale which foreshortens it. Example To make an isometric scale for drawing a cube. 1. Draw a horizontal line, a line at 45 degrees from it and a line at 30 degrees from it as shown. Label the 45º line the natural scale. Label the 30º line the isometric scale line Original size Iso scale Fig. 4: Isometric scale construction 2. Mark the length of the cube on the natural scale and drop a vertical to the isometric scale. This is the length used for drawing the cube in isometric projection.

6 A 3-D formal drawing 6 3. Draw the cube using the length as marked. Fig. 5: Cube drawn using isometric scale Spheres in isometric The isometric projection (scale) is primarily used in conjunction with spheres as the reduction in all measurements (except for the radius of the sphere) puts the two into proportion with each other. Example To draw a cube with a sphere on top in elevation and in scaled isometric full size OC A B Fig. 6: Elevation of cube and sphere Fig. 7: Radius of sphere marked on scales 1. The radius of the sphere is marked along the natural scale and a vertical dropped to the isometric scale.

7 3-D formal drawing 7 2. The centre of the sphere is found by taking the radius length from the isometric scale and marking it on the axial line as shown. 3. Now the natural scale is used to draw the radius of the sphere OC from centre B. Fig 8: Cube and sphere in scaled isometric Compare this drawing with Fig. 6, which shows the cube and sphere drawn in isometric but without the scaling. The cube looks far too large whereas in Fig. 8 the proportion looks correct. Figures 9 to 12 are all examples of spheres drawn to an isometric scale. Fig. 11 is drawn with an isometric scale but because it is not included with the drawing, an assessor may not recognise this as a scaled isometric drawing.

8 3-D formal drawing 8 Fig. 9: Line drawing

9 3-D formal drawing 9 Hel pful hint Rendering is not required for externals. Fig. 10: Isometric pictorial

10 3-D formal drawing 10 Fig. 11: Line drawing

11 3-D formal drawing 11 Hel pful hi int Rendering is not required for externals. Fig. 12: Isometric pictorial

12 3-D formal drawing 12 Activity 2: Isometric and scaled isometric drawing Draw the following as a scaled isometric projection. A Transfer Length A to Length B for the small radius at the end B Ø60 Sq Hemisphere Ø120

ENGINEERING GRAPHICS 1E9

Lecture 3 Monday, 15 December 2014 1 ENGINEERING GRAPHICS 1E9 Lecture 3: Isometric Projections Lecture 3 Monday, 15 December 2014 2 What is ISOMETRIC? It is a method of producing pictorial view of an object