Do you want to ask whether it is necessary to use CAD to draw a patent?
The answer is, not necessarily.
Just follow the general mechanical drawing requirements.
7.3 Drawings of the description
The drawings of the description shall be examined in accordance with the provisions of Article 19 and Article 39 of the Implementing Rules of the Patent Law. The review of the description drawings includes the following contents:
(1) Engineering blueprints and photos shall not be used in the drawings.
(2) The drawings should be drawn with drawing tools and black ink. The lines should be even and clear, and should not be colored or altered; there should be no frames around the drawings that are irrelevant to the drawings.
(3) The drawings should be numbered sequentially with Arabic numerals, represented by Figure 1, Figure 2, etc., and should be marked directly below the corresponding drawings.
(4) The drawings should be drawn vertically on the drawing paper as much as possible and clearly separated from each other. When the lateral dimensions of the parts are significantly larger than the vertical dimensions and must be arranged horizontally, the top of the drawing should be placed on the left side of the drawing. When there are more than two drawings on a page of drawings, and one drawing has been arranged horizontally, the other drawings on the page should also be arranged horizontally.
(5) The size and clarity of the attached drawing should ensure that all details in the drawing can still be clearly distinguished when the drawing is reduced to two-thirds.
(6) When a patent application contains multiple drawings, in each drawing used to represent the same embodiment, the reference sign indicating the same component (the same technical feature or the same object) should be consistent. The same reference signs used in the description and in the drawings shall indicate the same components. Reference signs that are not mentioned in the text of the description shall not appear in the drawings, and reference signs that do not appear in the drawings shall not be mentioned in the text of the description.
(7) The page numbers of the accompanying drawings in the manual should be numbered in Arabic numeral order.
(8) Except for necessary words, the drawings shall not contain other annotations; the words shall be in Chinese, and if necessary, the original text may be indicated in brackets.
(9) Structural block diagrams, logical block diagrams, and process flow diagrams should provide necessary text and symbols within their frames.
(10) The same drawing should be drawn at the same scale, and a partial enlarged drawing may be added to clearly show a certain component.