Motivation

• Nodes like Billboard and Anchor have built-in behavior
• You can create your own behaviors to make shapes move, rotate, scale, blink, and more
• We need a means to trigger, time, and respond to a sequence of events in order to provide better user/world interactions

Building animation circuits

Almost every node can be a component in an animation circuit

• Nodes act like virtual electronic parts
• Nodes can send and receive events
• Wired routes connect nodes together

An event is a message sent between nodes

• A data value (such as a translation)
• A time stamp (when did the event get sent)

Examples

To spin a shape:

• Connect a node that sends rotation events to a Transform node's rotation field

To blink a shape:

• Connect a node that sends color events to a Material node's diffuseColor field

Routing events

To set up an animation circuit, you need three things:

1. A node which sends events
   • The node must be named with DEF
2. A node which receives events
   • The node must be named with DEF
3. A route connecting them

Using node inputs and outputs

Every node has fields, inputs, and outputs:

• initializeOnly: A stored value
• inputOnly: An input
• outputOnly: An output

An inputOutput field is a short-hand for a initializeOnly, inputOnly, and outputOnly

Sample inputs

A Transform node has these input fields:

• set_translation
• set_rotation
• set_scale

A Material node has these input fields:

• set_diffuseColor
• set_emissiveColor
• set_transparency

Sample outputs

An OrientationInterpolator node has this output field:

• value_changed to send rotation values

A PositionInterpolator node has this output field:

• value_changed to send position (translation) values

A TimeSensor node has this output field:

• time to send time values

Syntax: ROUTE

A ROUTE statement connects two nodes together using

• The sender's node name and output field name
• The receiver's node name and input field name

ROUTE and TO must be in upper-case

Field data types

Sender and receiver field data types must match!

Data types have names with a standard format, such as:

• SFString,SFRotation, or MFColor

Following naming conventions

Most nodes have inputOutput fields.

If the inputOutput field name is xxx, then:

• set_xxx is an input to set the field
• xxx_changed is an output that sends when the field changes
• The set_ and _changed sufixes are optional but recommended for clarity

The Transform node has:

• rotation field
• set_rotation input
• rotation_changed output

A sample animation

Using multiple routes

You can have fan-out

• Multiple routes out of the same sender

You can have fan-in

• Multiple routes into the same receiver

Summary

• Connect senders to receivers using routes
• input fields are inputs, and output fields are outputs
• A route names the sender.output, and the receiver.input
  • Data types must match
• You can have multiple routes into or out of a node