# Creating an Equation Driven Curve

To create an equation driven curve:

1. On the Sketch toolbar, click the Spline flyout, and then select Equation Driven Curve or click Tools > Sketch Entities > Equation Driven Curve .
2. Under Equation Type, select Explicit or Parametric.
3D sketches support parametric equations only.
3. Under Equation, specify the curve equation where:
• Y is a function of X (explicit equations).
````x^3/"D1@Sketch5"`
```
You can use any functions supported in the Equations dialog box. For example:
````2*(x + 3*sin(x))`
```
• X, Y, and Z are functions of T (parametric equations). For example:

Let x be defined by: sin(t)

Let y be defined by: cos(t)

For t1 = 0 and t2 = pi, the result is a semi-circle. (Closed geometry is not allowed.)

Z is for 3D sketches only.

4. Under Parameters, specify the range of values for X (explicit equations) or T (parametric equations), where 1 is the start point and 2 is the end point (for example, X1 = 0 and X2 = 2*pi).
Click to lock or unlock the start or end point location on the curve:
• (locked): The start or end point is fixed.
• (unlocked): You can drag the start or end point along the curve.
5. Click .
The curve defined by the equation appears in the sketch.