# Epitrochoid

**Epitrochoid** is a is a curve traced by a point attached to a circle of radius **r** rolling around the outside of a fixed circle of radius **R**, where the point is a distance **d** from the center of the exterior circle.

The parametric equations for an **Epitrochoid** are

You can draw function online using the folowing script for **Epitrochoid**:

# Example |

Special case. **Epitrochoid** with **d = r**: Epicycloid

# Example |