Accurate representation of an object’s form is critical to the success of a design patent, and in many cases utility patents use shading as a tool to ease the examiner’s readability of a figure. Proper shading is critical for success of the patent as the creation of a realistic form will eliminate potential doubt in an examiners mind, as well as solidify the claims for future embodiments. There are a number of shading styles available for the patent illustrator to take advantage of, and there are situations where one may be more beneficial than another. Choosing the style of shading depends on the shape of the patent in question, and in some cases, shading styles are used to identify surface materials and textures.
Standard line shading is the common approach to surface shading, and there a number of variations of this style. This patent illustration style is preferred because is easily illustrates the precise geometry of a figure. Being able to show the solid line edge of a surface, next to perpendicular shading will allow you to understand the shape of that corner. Standard line shading is the preferred style for the majority of patent illustrations, especially the patents that have simpler forms and more of a geometric aesthetic. Line shading can be used to show transparent surfaces as seen in example F and G as well reflective surfaces as in example E.
Stipple shading is an alternative patent drawing technique, where the illustration uses varying densities of dots to demonstrate the figures form. In example C you can see how the use of stipple shading with varying density creates the rounded face needed for this figure. Patents that are of a more complex and organic nature may benefit from stipple shading, as there may not be easily define hard edges for a line. But if the design patent in question has a mixture of organic and geometric features, and hybrid stipple and line approach may be used to define the form, as seen by the technique used in example D. .
The average patent draftsmen will import your CAD or PDF files and create the figures from isometric vantage points, throw labels on, and send it back for you to review. They will add in some lines to help show a curve, or an angled surface, but they usually will not have the artistic skills to apply alternative shading techniques to a design patent. In some cases it may take longer, and require more skill to draft a stippled figure, but the ability for an examiner to understand a complex form and clearly identify aligning aspects of multiple views will leave the patent seeker with less office actions.