Curves can be used for many different things and there are several different controls in Unity that use curves that can be edited.
While these controls have subtle differences, the curves can be edited in exactly the same way in all of them. This page explains how to navigate and edit curves in those controls.
A key can be added to a curve by double-clicking on the curve at the point where the key should be placed. It is also possible to add a key by right-clicking on a curve and select Add Key from the context menu.
Once placed, keys can be dragged around with the mouse:
It is also possible to select multiple keys at once:
Keys can be deleted by selecting them and pressing Delete, or by right-clicking on them and selecting Delete Key from the context menu.
Direct editing of key values in curve editors is a new feature in Unity 5.1. Use Enter/Return or context menu to start editing selected keys, Tab to switch between fields, Enter/Return to commit, and Escape to cancel editing.
When working with the Animation View you can easily zoom in on details of the curves you want to work with or zoom out to get the full picture.
You can always press F to frame-select the shown curves or selected keys in their entirely.
You can zoom the Curve View using the scroll-wheel of your mouse, the zoom functionality of your trackpad, or by holding Alt while right-dragging with your mouse.
You can zoom on only the horizontal or vertical axis:
Furthermore, you can drag the end caps of the scrollbars to shrink or expand the area shown in the Curve View.
You can pan the Curve View by middle-dragging with your mouse or by holding Alt while left-dragging with your mouse.
A key has two tangents - one on the left for the ingoing slope and one on the right for the outgoing slope. The tangents control the shape of the curve between the keys. The Animation View have multiple tangent types that can be used to easily control the curve shape. The tangent types for a key can be chosen by right-clicking the key.
In order for animated values to change smoothly when passing a key, the left and right tangent must be co-linear. The following tangent types ensure smoothness:
Sometimes smoothness is not desired. The left and right tangent can be set individually when the tangents are Broken. The left and right tangent can each be set to one of the following tangent types: