Working with Sketch Curves in 3D

Use Enable 3D Sketch to switch to sketching mode in 3D.

You can use the following sketch tools in 3D mode:

Line	Line
Three-Point Circle	Three-Point Circle
Tangent Line	Tangent Line
Construction Line	Construction Line
Spline	Spline
Tangent Arc	Tangent Arc
Three-Point Arc	Three-Point Arc
Point	Point

You can use the following tools from the Sketch group to change curves in 3D mode:

Create Rounded Corner	Create Rounded Corner can be used on curves when they are coplanar.
Create Corner	Create Corner can also be used on coplanar curves.
Trim Away	Trim Away can be used to trim curves in 3D mode.
Split Curves	Split Curves can be used to split curves in 3D mode.