Three dimensional computer drawings for agricultural engineering

Abstract

The sort of three dimensional computer drawings described here are often used as eye catching gimmicks on the front covers of books and journals. It is not often, though, that the way in which these drawings are made is described. In this report the computer drawing technique is outlined in broad terms for the general reader while the details needed to run such a program are provided in an Appendix. Any phenomenon which can be represented as a surf ace can be presented graphically using this computer generated method. The results can often be more easily grasped by both engineers and laymen than description by means of contour plans, mathematical formulae, coefficients of variation,or other mathematical or statistical methods. These three dimensional drawings have a variety of agricultural engineering applications. They have been used as an aid in planning the most suitable earthmoving operations when preparing land for horticulture as the various earthwork patterns can be seen at a glance. The visual representations, together with the costs, assist in decision making (see Figure 1). They have also been used to display the variations in the quantity of water applied to the soil by irrigation sprinklers, and the effect of wind on sprinkler performance (see Figures 2 and 3) . In the future it may be possible to use these projections when planning complex irregular border-dyke irrigation layouts. At present these constitute a difficult problem. If a designer takes the trouble to present a complex layout in detail it is difficult for the machinery operators to interpret the plan in the field. A visual representation may help in meeting both the design and the cost objectives. The examples show the flexibility of the method and the extent to which these three dimensional drawings can be useful to agricultural engineers. Workers in other fields may also find applications for this method of presentation. The cost of producing any one of the computer drawings illustrated here is no more than about $1.00 at commercial computer charge-out rates.