Line weights

Lineweights add width to your objects, both on screen and on paper. Using lineweights, you can create heavy and thin lines and vary object thicknesses in details. Just as heavy and thin lead weights are used in manual drafting, lineweights can be used to graphically represent different objects and types of information. The figure below shows line thickness applied to wall entities while others are left at the default (thin) setting.

Line thickness

You should not use lineweights, however, to represent the exact width of an object. For example, if you want to draw an object with a real-world width of 150 millimeters, you should not use a lineweight; instead, use a polyline with a width of 150 millimeters to represent the object accurately.

Lineweights are displayed differently in model space than in a paper space layout. In model space, lineweights are displayed in relation to pixels. In a paper space layout, lineweights display in the exact plotting width. Lineweights should be used for the graphic representation of different objects and types of information, and are, therefore, displayed in model space in proportional pixel values. You can recognize that an object has a thick or thin lineweight in model space but the lineweight does not represent an object's real-world width. A lineweight value of 0 is displayed as one pixel in model space and print at the thinnest lineweight available on the specified printer. All other lineweights are displayed using a pixel width in proportion to its real-world unit value.

Lineweight display in model space does not change with the zoom factor. For example, a lineweight value that is represented by a width of four pixels is always displayed using four pixels regardless of how far you zoom into your drawing.

You can set the display scale of lineweights if you want the lineweights on objects to appear thicker or thinner at model space. Changing the display scale does not affect the lineweight plotting value. However, a drawing's redraw time increases with lineweights that are represented by more than one pixel.

At any time you can turn lineweight display on/off by pressing Ctrl+T.