How to Create an Equation Driven Curve in SOLIDWORKS

An equation driven curve creates sketch geometry from a mathematical equation. It is useful for spirals, parabolas, sine waves, custom paths, and profiles that are easier to define with an equation than by manual sketching.

Start the curve command

1. Open or create a sketch.
2. Go to Tools > Sketch Entities > Equation Driven Curve.
3. Choose explicit or parametric equation input.
4. Enter the equation and range values.
5. Preview the curve before accepting it.

Choose explicit or parametric

An explicit equation defines one variable directly from another, such as y as a function of x. A parametric equation defines x and y from a parameter. Parametric input is often better for curves that loop, spiral, or cannot be described cleanly as one y value for each x value.

If you are not sure which type to use, start with the simplest equation that describes the shape. You can always rebuild the curve with a parametric definition if the explicit version cannot represent the full geometry.

Set the range carefully

The start and end values control how much of the curve SOLIDWORKS creates. If the range is too small, the curve may not cover the needed area. If it is too large, the curve may become hard to use or slow to rebuild.

Use known design limits for the range instead of guessing. For example, if the curve is a sweep path inside a part, set the range so it covers only the useful portion of the path.

Use the curve in features

Equation driven curves can become paths for sweeps, guide curves, split lines, or reference geometry. Before using the curve in a feature, make sure it is smooth and positioned correctly relative to the rest of the model.

After creating the curve, add reference dimensions or construction geometry to help confirm placement. Mathematical curves can look correct visually while still being offset from the intended origin.

Keep equations readable

Use simple expressions where possible and keep a note of what each variable represents. If another user needs to edit the model later, a readable equation is much easier to maintain than a complicated expression with no explanation.

Troubleshooting

If the curve fails, check the equation syntax, range values, and units. Start with a simple equation first, then add complexity once the curve previews correctly. If the curve is for a manufactured feature, verify the final dimensions after creating it.

If the curve creates too many tiny segments or makes the model slow, simplify the equation or reduce the range. A clean curve that rebuilds reliably is usually better than an overly complex one.