The benefits of clear surface shading in a design patent were highlighted in a recent district circuit decision, which found that purported contour or tangent edge lines added to the drawings to illustrate a transition edge between rounded and flat surfaces were not proper lines to indicate surface contour, but instead claimed features.
Morgan D Rosenberg - Patent Application Drafting-LexisNexis
Industrial Design Office Practices (Page 4 of 4)
The Scope of Comparison Prior Art in Design Patent Infringement
Court Interprets Purported Contour Lines in Design Patent Drawings
The Scope of Comparison Prior Art in Design Patent Infringement
Court Interprets Purported Contour Lines in Design Patent Drawings
design patent Archives - Eric Waltmire's Blog
IN DESIGN PATENT DRAWINGS, WHEN ARE LINES LINES, AND WHEN ARE
Ethicon v. Covidien - Order Granting SJ, PDF
The Use of Line Patterns in Patent Drawings, PatSketch
design patent Archives - Eric Waltmire's Blog