A line whether straight or curved tells a story about everything that is around us. We can understand a lot just looking at the lines that create a complete image of a product.
Lines of different thickness clarify a form and add dynamics to a sketch. Choosing a thick or thin line you have ability to emphasize chosen parts of an object. It can lead viewers to most important aspects of a product.
Depending on a tool, you get lighter or heavier line. It is also important how much force do you use to create a line. Some tools have soft nibs and this way you can variate with line sizes depending on a force you use.
It’s not that necessary to have multiple tools (fine liners, ballpoint pens, markers with different nibs) but the important thing is to be able to draw a straight line. A line is a product designers’ language for expressing their ideas and a crooked, unsure line won’t leave a good impression.
A tip to draw straight lines: use your shoulder and not the wrist to create aligned lines. It gives more control through the complete stroke.
Basic Line Weight Usage
- The thinnest line is used to describe the edges of a product that point towards a viewer and also for the inner lines.
- Second thickness lines are used for outlines (edges that have air behind them). These are not only contour lines, but can also occur within an object.
- The thickest lines are used for the baselines – lines that show the interface between a product and a ground plane.
In the image above you can see how the look of simple geometric shapes changes due to various line thickness. Take a look at the drawing to see how some lines emphasize certain edges of a shape.
Exaggerating the Contour Line
Exaggerating contour lines can bring an object forward, pushing other objects into the background and this way adding a depth to a picture.
Thick contour lines are used to determinate which object is most important in a sketch.
There are other line weight effects one can use to improve the overall quality of a sketch. Examples – showing lighting by thickening shadow side edges and using thinner lines on light side edges. You can also improve perspective by decreasing the line weight as the lines stretch further from a viewer.
In the image below you can see how multiple variations of a line thicknesses change the look of cubes and how some of them look three dimensional and others are flat.
