Patent Drawing 101:

Understand Shading Requirements

For Design Patent Drawings

NVG mascot lead line leddy (roange arrow attached to letters NVG and a face) holding a pencil and standing amongst geometric shapes drawn in a 3d style with line straight line shading to indicate contours

nvg mascot lead line leddy holding a line drawing of a cube that has shade lines to make it look transparent and he is saying in a speech bubble "shading's not decoration - it's dimension!"

Shading in patent drawings communicates the three-dimensional form of an object. It’s especially crucial in design patents where the appearance, not the function, is being protected.

Shading is used for:

Depicting surface contours

Distinguishing between flat and curved surfaces

Clarifying shape and depth

Recognizing transparent or reflective materials

Acceptable Shading Methods

According to the USPTO

one cube line drawing with straight lines on the visible sides that indicate a flat surface, and a curved geometry with straight lines indicating a curved surface

STRAIGHT-LINE SHADING

Parallel lines for curved or contoured surfaces

two circles both with many small black dots or points that indicate a 3-dimensional condition

STIPPLING

Dots used to show texture, especially for matte or metallic surfaces

cylindrical shape with straight lines to indicate shading/contours and on top of it sits a circle that is shaded using small tiny dots arranged to gradually change densities

COMBO

Line shading and stippling be used in the same drawing to show contrast ↓

BUT… Do NOT mix them on the same surface!

Types of Surface Shading

For different geometries

Shading isn’t one-size-fits-all. Each surface type calls for a specific shading approach to properly communicate volume and geometry.

Transparent

Cylindrical

Convex

a line drawing of a cube with straight lines arranged on each visible surface in the direction of the axis on which the surface planes sit

Flat

Hollow

Concave

a rectangular prism line drawing with short straight lines arranged slightly offset from each other, forming "strips" along the surfaces, drawn facing different directions on each surface to distinguish them

Flat/Strip

a circle drawn with broken line concentric circles consequently placed inside of it, implying a 3-D shape like a sphere rather than 2-D circle

Spherical

Bevel

a triangular prism line drawing with lines parallel to its base arranged on its surface getting denser towards the highest/furthest part of the surface

Diagonal

a torus shape whose lightly soft edges are characterized by broken shade lines offset from the outermost curves/edges of the shape

Transition

top view of a beveled circular object that appears as two concentric circles with lines radiating 360 degrees between them to show the contour of the beveled surface

Bevel (top)

Common Shading Mistakes:

🚫 Inconsistent line direction or spacing

🚫 Mixing stippling and line shading on the same surface

🚫 Shading flat areas unnecessarily

🚫 Using color or gradients (unless color is being claimed)

Even good drawings can get flagged if the shading is off. Avoid these common mistakes that could lead to confusion—or an office action.

nvg mascot lead line leddy frowning and holding up a thumbs down

nvg mascot lead-line leddy lowering a pair of sunglasses and saying "Just here to make sure your shading checks out"

While shading is often essential, there are situations where leaving it out is the better choice. Overusing or misapplying shading can clutter your drawings or confuse the examiner.

When NOT to Use Shading

🚫 The surface is flat and clearly defined

🚫 Shading would obscure important details

🚫 Your drawing already communicates form effectively without it

Protect Your Patent with Precision

Patent drawings may look simple, but every line carries legal weight.

At Northern Virginia Graphics, we do more than draw. We guide, question, and deliver illustrations that meet USPTO expectations with precision and clarity.