- Understanding Solid Objects
- Understanding Sketching Techniques
- 3.1 Technique of Lines
- 3.2 Sketching Straight Lines
- 3.3 Sketching Circles, Arcs, and Ellipses
- 3.4 Maintaining Proportions
- 3.5 One-View Drawings
- 3.6 Pictorial Sketching
- 3.7 Projection Methods
- 3.8 Axonometric Projection
- 3.9 Isometric Projection
- 3.10 Isometric Drawings
- 3.11 Making an Isometric Drawing
- 3.12 Offset Location Measurements
- 3.13 Hidden Lines and Centerlines
- 3.14 Angles in Isometric
- 3.15 Irregular Objects
- 3.16 Curves in Isometric
- 3.17 True Ellipses in Isometric
- 3.18 Orienting Ellipses in Isometric Drawings
- 3.19 Drawing Isometric Cylinders
- 3.20 Screw Threads in Isometric
- 3.21 Arcs in Isometric
- 3.22 spheres in Isometric
- 3.23 Oblique Sketches
- 3.24 Length of Receding Lines
- 3.25 Choice of Position in Oblique Drawings
- 3.26 Ellipses for Oblique Drawings
- 3.27 Angles in Oblique Projection
- 3.28 Sketching Assemblies
- 3.29 Sketching Perspectives
- 3.30 Curves and Circles in Perspective
- 3.31 Shading
- 3.32 Computer Graphics
- 3.33 Drawing on Drawing
- Key Words
- Chapter Summary
- Worksheets
- Review Questions
- Sketching Exercises
This chapter is from the book
This chapter is from the book
This chapter is from the book
3.4 Maintaining Proportions
Sketches are not usually made to a specific scale, although it can be handy to do so at times. The size of the sketch depends on its complexity and the size of the paper available. The most important rule in freehand sketching is to keep the sketch in proportion, which means to accurately represent the size and position of each part in relation to the whole. No matter how brilliant the technique or how well drawn the details, if the proportions are off, the sketch will not look right.
To maintain proportions, first determine the relative proportions of height to width and lightly block them in. You can mark a unit on the edge of a strip of paper or use your pencil (as in Figure 3.28) to gauge how many units wide and high the object is. Grid paper can help you maintain proportions by providing a ready-made scale (by counting squares). As you block in the medium-size areas, and later as you add small details, compare each new distance with those already established.
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3.28 Estimating Dimensions
STEP by STEP: MAINTAINING PROPORTIONS IN A SKETCH
If you are working from a given picture, such as this utility cabinet, first establish the relative width compared to the height. One way is to use the pencil as a measuring stick. In this case, the height is about 1-3/4 times the width.
Sketch the enclosing rectangle in the correct proportion. This sketch is to be slightly larger than the given picture.
Divide the available drawer space into three parts with the pencil by trial. Hold your pencil about where you think one third will be and then try that measurement. If it is too short or long, adjust the measurement and try again. Sketch light diagonals to locate centers of the drawers and block in drawer handles. Sketch all remaining details.
Darken all final lines, making them clean, thick, and black.
STEP by STEP: HOW TO BLOCK IN AN IRREGULAR OBJECT
Capture the main proportions with simple lines.
Block in the general sizes and direction of flow of curved shapes.
Lightly block in additional details.
Darken the lines of the completed sketch.
STEP by STEP: GEOMETRIC METHODS FOR SKETCHING PLANE FIGURES
Sketching a Polygon by the Triangle Method
Divide the polygon into triangles as shown. Use the triangles as a visual aid to sketch the shape.
Sketching a Polygon by the Rectangle Method
Imagine a rectangle drawn around the polygon as shown.
Sketch the rectangle and then locate the vertices of the polygon (points a, b, c, and so on) along the sides of the rectangle.
Join the points to complete the shape.
Visual Aids for Sketching Irregular Figures
Visualize shapes made up of rectangular and circular forms by enclosing those features in rectangles.
Determine where the centers of arcs and circles are located relative to the rectangles as shown.
Sketch the features inside the rectangular shapes you have lightly blocked in and darken the final lines.
Creating Irregular Shapes by Offset Measurements
Enclose the shape in a rectangle.
Use the sides of the rectangle as a reference to make measurements that locate points along the curve.
Enlarging Shapes Using a Grid of Squares
Complex curved shapes can be copied, enlarged, or reduced by hand, if necessary.
Draw or overlay a grid of squares on the original drawing.
To enlarge, draw the containing rectangle and grid of squares at the desired percentage and transfer the lines of the shape through the corresponding points in the new set of squares.
