A ValueNode is a value that can change over time.
A ValueNode represents a description of a value and how it changes (or doesn't!) over time.
ValueNodes are the things we see as the value for every parameter of every layer. The waypoints visible in the timetrack dialog are also part of the ValueNode - waypoints are how Animated ValueNodes work out what value to be at each point in time.
There are three kinds of ValueNodes in Synfig. In the following examples the ValueNode's type is a real number in each case:
These have a single value for all time, and no waypoints. An example of such a ValueNode would be:
"3.4, for ever"
These have Waypoints that specify their value at particular points in time. For times which don't have a value specified, the value is calculated by interpolating between the waypoints. An example would be:
"3.4 at the beginning of the animation, move smoothly up to 7.6 at time = 10 seconds, then jump instantly to 2.0 and stay there until the end of time"
These are ValueNodes which have been Converted into sub-parameters, each of which is itself a ValueNode. Right-clicking on a parameter and selecting a type from the 'convert' sub-menu allows you to convert a ValueNode. Converted ValueNodes don't have waypoints themselves, but their sub-parameters may do. An example would be:
"start at 3.4 and linearly increase by 1.2 per second"