In this tutorial, we will learn the basics of curves and how objects instance using Curves in Geometry nodes. Blender version **3.0**.

Curves are expressed using Mathematical expressions and usually, they are not linearly interpolated. They are defined by less data and they consume less memory.

Curves are very useful when extruding a profile along a path.

Curves have three major parts.

- Control Point
- Segment
- Handle

Like mesh has vertices, the curve has control points which can be transformed. Segment is the path formed by curve. Handle are used to define the bending of the curve.

In Blender, there are two types of curves.

- Beizer Curve
- NURBS Curve

Beizer curve always passes through the control point. It touches the start and endpoint of the segment.

NURBS curve does not necessarily pass through the control points, rather it bends towards them. And it doesn’t end on the endpoint.

When using curves in Geometry Nodes, if we use Instance on Points on a curve, the objects instance on the control points. So, it is important to understand the basics of the curves.

In this next tutorial, we will will learn how we can use Geometry Nodes to instance on curves: Instancing the objects using Instance on Points.

A Procedural Spiral Stairacse can be made using curves in Geometry nodes.