Technical data

Working with AutoCAD Land Development Desktop Drawing Tools to Create Lines and Curves
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Drawing Spiral Curves
Spiral curves are often used in roadway design to achieve more gradual
transitions. Instead of having a constant rate of curvature like an arc,
the spiral’s curvature is adjusted throughout—a more gradual
curvature at the beginning, and then increasing the curvature until
the SC (spiral-to-curve) intersection is reached.
AutoCAD Land Development Desktop supports four types of
spirals: Clothoid, Quadratic, Cosinusoidal, and Sinusoidal. Each
spiral type has a different rate of curvature, as shown in the
following illustration.