Dotted lines are also used to show a change of position or an alternate position of some part, as, for example, the lines L K and J L show that the side J K of the top view has been swung around on the point K until it occupies the position shown by L K, its extremity J traversing the line J L. When it is necessary to use two kinds of dotted lines, those used for one purpose may be made in line or short dots, while the others may be made a series of short dashes.

Lines showing the part of a view through which a section is taken are composed of a series of dots and dashes, as shown by A B, C D, etc.. in Fig. 128, and when further distinction is required may be made by two dots alternating with a short or long dash.

When it is desirable to omit the drawing of a considerable portion of any view it is customary to terminate the incomplete side of such view by an irregular line, as shown above the plan G in Fig. 128.

It is customary in all sectional views for the parts which are represented as being cut to be ruled or lined with lines running in an oblique direction, as in Fig. 189. When the section comprises several different pieces lying adjacent to one another, each different part should be lined in a different direction. This ruling is understood to mean solidity. In Fig. 129 the walls and base in the different, sections are represented as though made of some solid material, as wood or stone, and ruled accordingly. Where it is necessary to represent different kinds of material in the same section, different systems or kinds of lines may be used for the purpose. Thus solid and dotted lines may be used alternately, as in the base. Coarse and fine ruling, or stippling, may also be employed, according to the size of the part, or very small parts may be shown solid black, as window weights, piping or hinges. A heavy line is the only way that a thickness of metal can properly be shown in a section. In the case of a sectional view of a cornice or molding where nothing but the sheet iron appears, it is customary to make use of section lines close to the metal surface, but not to extend them clear across the space which should be tilled if the moldings were of stone or other solid material. By this means a section may be distinguished from what might otherwise be taken for an elevation of a return.

In the case of elaborate drawings prepared by an architect color is frequently resorted to as a means of showing the different materials as they appear in the sectional view, yellow or differing shades of brown being used for various kinds of wood, while blue is generally used for iron, gray for stone, red for brick, etc. In the case of drawings showing many different materials it is usual to place a legend in one corner of the drawing showing what each color or style of ruling indicates.

It is always advisable to keep the different views, which it is necessary to construct, separate and distinct from one another, drawing them as near together as circumstances will permit, but never allowing one view to cover any part of the space upon the paper occupied by the other view if it can be avoided. One notable exception to this rule is to be observed. It frequently occurs in drawing an elevation of a large surface, as a pediment or side of a bracket, that it is necessary to indicate that some part of it is recessed or raised, or that a certain edge is molded or chamfered, when it would not be necessary to construct an entire sectional view for this purpose alone. To this end it is customary to draw through such mold, chamfer or recess a small section, in which case, if the depression or mold runs horizontally, the section is turned to the right or left, according to convenience, or if it runs obliquely, it is turned in the direction the mold runs. In such a section the line which represents the plane surface also shows the direction of the cut across the mold or line upon which the section is taken. In Fig. L80 is shown an elevation of a portion of a pediment, in which a small section. A B C, is introduced to show the profiles of the moldings. The line 13 C, which represents the profile of the stile around the panel, shows the line upon which, or the direction in which, the section is taken, said section being turned upon this line obliquely to the left. It is necessary to rule or line this section, the ruling being kept close to and inside the outline or profile. By placing the ruling inside the profile no doubt can exist as to which pint-are raised and which are depressed, for if at D the ruling were upon the other side of the line from that shown the section D would indicate a depressed panel instead of a raised one.

Fig. 130.   Elevation with Section, of Parts.

Fig. 130. - Elevation with Section, of Parts.

In the solution of the class of problems treated in Chapter VI (Pattern Problems), Section 1 (Miter Cutting), confusion often arises in the mind of the pattern cutter as to the proper position of a profile or of a miter line, which confusion could never occur if all the necessary views were first drawn in accordance with the principles which this chapter is written to explain. A profile is always a section, and a miter line is either a part of an elevation projected from the section or part of another section bearing certain relations of Light or breadth to the first. A pattern is likewise always projected - that is, carried off by right lines - from an elevation or plan the same as an elevation is projected from a section.

It should also be remembered in this connection that the operation of developing a pattern is not completed until its entire outline is drawn. The line forming its termination at the end opposite the miter cut, although simply a straight line, is properly derived from the elevation or plan used, the same as all points and other lines of the pattern.

Much trouble is experienced through lack of knowledge of the principles of Linear Drawing, which if thoroughly understood could never result in such mistakes as producing a face miter where a return was intended or using the piece of metal from the wrong side of the miter cut.

Too much emphasis cannot be placed upon the importance of thoroughly understanding the subject treated in this chapter, as such a knowledge comprehends within itself an answer to the many questions continually arising in the course of the pattern draftsman's labors.