Chapter 6 - Isometric Projection and Basic Shapes

Basic Shapes Problem

For visualizing a solid object, and for dimensioning it later on in this course, it may be thought of as being composed of a number of basic shapes such as those shown on the linked page titled "Basic Shapes". You should therefore, begin to think about how an object can be broken down for analysis. These basic shapes are some of the building blocks used to create 3D solid models, and are referred to as primitives in many 3D modeling software packages.

Based on the assumption that it will be easier for you to read a drawing that you have made than to read one that someone else has made, you will have the opportunity to make up your own problem. In this problem, you will form a solid object.

In arranging these basic shapes, the following should be observed:

2. When two identical shapes are to be assembled, they should not be mated with one common surface. Figure 1, illustrates how not to combine two identical shapes.

3. The various shapes should be assembled with sufficient surface contact to make the object stable. A line or a point of contact is not sufficient. Figure 2

4. For the tabulated data for each problem, one column headed "Remarks" is for information as to whether or not shapes are to be added or subtracted. Figure 3 illustrates shapes which have been added. Figure 4 illustrates shapes which have been subtracted.

You will be assigned certain basic shapes, their size (scale), quantity of each shape, and whether to add them or remove them from your model. You are required to arrange these shapes so as to form a solid object. After you have thought out your composition, you are required to draw, mechanically or freehand as assigned by your instructor, an isometric drawing and a three view orthographic drawing composed of a front view, a top view, and a right side view. To obtain the correct proportion, let the spaces on both the isometric and orthographic grids represent 1/4. You may draw either the isometric or the orthogrphic drawing first. In either case, one will be an aid in drawing the other.

In the isometric drawing, omit the hidden lines.

In the orthographic drawing, consider the object as being solid. Show all visible and all hidden lines. Do not number the shapes.

Draw your solution on the back of the graph paper provided, with the isometric grid in the upper right hand corner.

In all cases, the three picture planes used in the orthographic views must be the same three visible planes in the isometric drawing.

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