GL-PCT A V 7.5.1 Leading lines

Reference lines (also referred to as leading lines), that is, lines between the reference signs (for example, reference numerals) and the details referred to, may be straight or curved and should be as short as possible. They must originate in the immediate proximity of the reference sign and extend to the feature indicated. Reference lines for certain reference signs may be omitted. Reference signs of this type, which are not connected to anything, will then indicate the surface or cross-section on which they are placed.

GL-PCT A V 7.5 Numbers, letters and reference signs

Numbers, letters, reference signs and any other data given on the sheets of drawings, such as the numbering of figures and of the sheets, acceptable text matter, graduations on scales, etc., must be simple and clear, and not used in association with any brackets, inverted commas, circles or outlines whatsoever. Signs indicating minutes, seconds or degrees are permitted. Numbers, letters and reference signs should be laid out in the same direction as the diagram so as to avoid having to rotate the sheet.

GL-PCT A V 7.4 Scale of drawings

The scale of the drawings and the distinctness of their graphical execution must be such that a photographic reproduction with a linear reduction in size to two-thirds would enable all details to be distinguished without difficulty. In exceptional cases, where required, the scale of the drawing may be graphically represented.[R. 11.13(c); ]

GL-PCT A V 7.3.2 Hatching

A cross-section must be set out and drawn in the same manner as a normal view whose parts in cross-section are hatched with regularly spaced parallel oblique strokes, the space between the strokes being chosen on the basis of the total area to be hatched. Hatching should not impede the clear reading of the reference signs and reference lines. Consequently, if it is not possible to place reference signs outside the hatched area, the hatching may be broken off wherever reference signs are inserted. Certain types of hatching may be given a specific meaning.

GL-PCT A V 7.3.1 Sectional figures

Where a figure is a cross-section of another figure, the latter should indicate the position of the section and may indicate the viewing direction by arrows at each end. In addition, in order to allow each sectional figure to be quickly identified, especially where several cross-sections are made of the same figure, each end of the cross-section line should be marked on the diagram with the same single Arabic or Roman numeral which identifies the figure in which the section is illustrated.[]

GL-PCT A V 7.3 Cross‑sections

7.3.1 Sectional figures

7.3.2 Hatching

GL-PCT A V 7.2 Shading

The use of shading in figures is allowed provided this assists in understanding them and is not so extensive as to impede legibility. Shading may, for instance, be used to indicate the shape of spherical, cylindrical or conical elements. Flat parts may also be lightly shaded. Such shading is allowed in the case of parts shown in perspective but not for cross-sections. Only spaced lines may be used for shading, not fully blacked out areas. These lines must be thin and as few in number as possible and contrast with the rest of the drawings.[]

GL-PCT A V 7.1 Drawings of lines and strokes

The drawings must be executed in durable, black, uniformly thick and well-defined lines and strokes. See GL/PCT-EPO A-V, 1.2, in respect of colour drawings, where these are exceptionally submitted. In all cases, the thickness of the lines and strokes must take into account the scale, nature, execution and perfect legibility of the drawing and of the reproductions.

GL-PCT A V 7 Execution of drawings

7.1 Drawings of lines and strokes

7.2 Shading

7.3 Cross‑sections

7.4 Scale of drawings

7.5 Numbers, letters and reference signs

GL-PCT A V 6 Prohibited matter

As set out in Rule 9.1(i) and (ii), the international application must not contain drawings contrary to morality or public order. If it does, the applicant may be invited to voluntarily correct it (Rule 9.2).[]