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gave in the preceding chapter is
ly is of value in making the drawing very clear and distinct. There is also another method of shading, which, however, is much more difficult of execution.
This style of shading we show in Figs. 62, 63 and 64, and in order to be able to use it to good effect, considerable experience and practice is necessary. It is used more for ornamental purposes than for practical purposes, but still, no book on drawing would be complete without some attention to it. It is seldom or never that a drawing of any extent would be shaded throughout in this manner, but our readers will find, if they do much in the way of drawing, that its use will often be a valuable aid in showing up apparatus of different kinds, portions of plain drawings that are desired to be brought out with great clearness, etc.
In the use of this shading, coere are exact rules that are laid down as to the point which should be shaded heaviest, as well as lightest. It will be sufficient, however, for our purposes to make this instruction very brief and to the point.
The results seen in Nos. 1 and 2, of Fig. 62. are obtained by giving the greatest shade effect to the right hand side of the figure, the lightest point being about midway, and the left hand side being shaded somewhat, though not so heavily as the right hand side. These two figures represent solid cylindrical figures. No. 3, a hollow cylindrical figure is shaded in exactly an opposite manner, that is, with the heaviest shading at the left, medium shade effect at the right, but with the lightest point still near the center. No. 4, a horizontal solid cylinder, is shaded
heavy at the bottom, and medium at the the shade lines of the branch should end top, while No. 5, a horizontal hollow cyl. at those lines. inder is shaded in an opposite manner, Fig. 64 shows the principle of line as will readily be seen. Additional ef- shading applied to a system of piping. fect is gained by using the heavy shade As we have already intimated, this lines as described in the preceding ar work is more ornamental than otherwise, ticle.
and a knowledge of its use will often be In drawing these shade lines, the ef- found handy. As our regular practice excect of shade is gained entirely by the ercise, we give this time, Fig. 65, an ele closeness of the lines together, the heavy vation of the hot and cold water supply shading being produced by drawing the system for a two-flat house, and have lines closely together and the light shad. shown the lines of pipe as single lines, ing by giving considerable space between the cold pipes being represented by solid the lines, additional effect being given by lines, and the hot by dotted lines. This breaking the lines as appears on most of method is often preferable to using two the figures. The skill in doing this work parallel lines to show the pipe, as it is comes from the ability to vary the spaces simpler to draw, takes less time, and often between the lines in such a manner that shows off the work fully as clearly. It the figure will appear cylindrical at all will be understood that our illustrations points, and nowhere flat, as it would it being designed for reproduction as cuts in the spacing was not varied continually. a paper, have to be drawn in black ink.
The greater the diameter of the cylin. Under ordinary conditions, different coldrical figure, the greater should be the ored inks could be used to advantage, space between lines at the lightest point. however. For instance, instead of dotThe proper spacing of these lines is gained ting the hot water pipes, as we have to only from practice, it being a thing that in this case to make our distinction from cannot be reached from any exact instruc- the cold water, the hot water pipe might tions, or from measurement.
be put in with solid red lines, with good To those who are not interested in the effect. If desirable, a back air system inking of drawings, we would say that might be put in with one color, while a this shading can be done also with lead different color was used on the drainage pencil. In Fig. 63, No. 1 shows an el. part of the work. bow shaded. The curved lines are all Sometimes, also, it is required to make struck from the one center, and should a drawing in which part of the work is be put in first, and the straight lines con- old work, and the rest new work. In this nected with them afterward. In shading case, one color to show the old and an. branches, as Nos. 2 ard 3, the lines of other to show the new, makes good work, intersection should be drawn in first, and and is more readily distinguished,
concerning sectional draw- boring pieces must be made by reversing
valuable aid in the clear rep- posite angles, just as No. 2 shows. It resentation of many kinds of work, it will be observed that in drawing the secwill be worth our while to devote some space to their consideration. From a comparison of Nos. 1 and 2 in Fig. 66, we shall be able to see wherein the value of sectional drawings lies.
No. 1 represents a Fuller bibb, and the dotted lines represent the inside working parts.
No. 2 represents the same thing, but in. stead of drawing a plain view as in No. 1, the bibb is considered to be cut through along the center line, and the front balf
NO. set aside. This allows a full view of the other half. A sectional view of the bibb is a view of this half section such as No. 2 gives, and it will be seen at once that the sectional view is far clearer than that shown by No. 1. To show that it is a sectional drawing, the part that is cut through is always sectioned or crosshatched. By this is meant the parallel lizes drawn close together, which desigaate the body of the bibb. These lines may be drawn with either the 45 deg. or 30 deg. triangle. Every point of any given piece should be sectioned in the
No 2. same way. For instance, the inlet end of the bibb, which screws onto the body, is represented in the drawing by a section of metal above the center, and one below, both of which, being a part of the same piece, should be sectioned by lines drawn in the same direction and at the tion the working parts have been drawn same angle. It is often the case that plain, and not in section. The idea is al. these sections are represented by differ ways to make any drawing show the obent colors instead of section lines, the dif- ject it is made to represent with the ferent colors representing different pieces greatest possible amount of clearness, and of the article in question.
it will be found in this case that the bibb When section lines are used, and the is shown much more clearly by leaving different sectioned parts are in contact the working parts plain, instead of sec