Is a drawing an essential element of a design patent application?
Every design patent application must include either a drawing or a photograph of the claimed design. As the drawing or photograph constitutes the entire visual disclosure of the claim, it is of utmost importance that the drawing or photograph be clear and complete, and that nothing regarding the design sought to be patented is left to conjecture.
The design must be represented by a drawing that complies with the requirements and must contain a sufficient number of views to constitute a complete disclosure of the appearance of the design. Appropriate and adequate surface shading should be used to show the character or contour of the surfaces represented. Solid black surface shading is not permitted except when used to represent the color black as well as color contrast. Broken lines may be used to show visible environmental structure, but may not be used to show hidden planes and surfaces that cannot be seen through opaque materials. Alternate positions of a design component, illustrated by full and broken lines in the same view are not permitted in a design drawing. Photographs and ink drawings are not permitted to be combined as formal drawings in one application. Photographs submitted in lieu of ink drawings in design patent applications must not disclose environmental structure but must be limited to the design claimed for the article.
The answer to this question can be found in chapter 1500 of the MPEP. This chapter covers Design Patents.
The answer is from the 9th Edition, Revision 08.2017. Depending on future changes to the MPEP, the question and answer may or may not be applicable in later Editions or revisions.
This question and answer comes from section 1503.02 of the MPEP. The following is a brief summary of section 1503.02.
This section covers drawings in design patent applications. It covers topics such as views, the use of surface shading and surface treatments, using broken lines, and photographs and color drawings. For instance, drawings are normally required to be submitted in black ink on white paper.