Motivation
You can group shapes to compose complex shapes
X3D has several grouping nodes, including:
XML Encoding
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<Group><!-- ... --></Group> <Switch><!-- ... --></Switch> <Transform><!-- ... --></Transform> <Billboard><!-- ... --></Billboard> <Anchor><!-- ... --></Anchor> <Inline/> <!-- and more --> |
Classic Encoding
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Group { ... } Switch { ... } Transform { ... } Billboard { ... } Anchor { ... } Inline { ... } and more |
Syntax: Group
The Group node creates a basic group.
- Every child node in the group is displayed.
XML Encoding
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<Group> <!-- children ... --> </Group> |
Classic Encoding
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Group { children [ ... ] } |
Syntax: Switch
The Switch group node creates a switched group
- Only one child node in the group is displayed
- You select which child
- Children implicitly numbered from 0
- A -1 selects no children
XML Encoding
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<Switch whichChoice='0'> <!-- children ... --> </Switch> |
Classic Encoding
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Switch { whichChoice 0 children [ ... ] } |
Syntax: Transform
The Transform group node creates a group with its own coordinate system.
- Every child node in the group is displayed.
XML Encoding
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<Transform translation='0.0 0.0 0.0' rotation='0.0 1.0 0.0 0.0' scale='1.0 1.0 1.0'> <!-- children ... --> </Transform> |
Classic Encoding
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Transform { translation 0.0 0.0 0.0 rotation 0.0 1.0 0.0 0.0 scale 1.0 1.0 1.0 children [ ... ] } |
Syntax: Billboard
The Billboard group node creates a group with a special coordinate system.
- Every child node in the group is displayed.
- The coordinate system is turned to face viewer.
XML Encoding
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<Billboard axisOfRotation='0.0 1.0 0.0'> <!-- children ... --> </Billboard> |
Classic Encoding
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Billboard { axisOfRotation 0.0 1.0 0.0 children [ ... ] } |
Billboard rotation axes
- A rotation axis defines a pole to rotate round
- Similar to a Transform node's rotation field, but no angle (auto computed)
- A standard rotation axis limits rotation to spin about that axis
- A zero rotation axis enables rotation around any axis
| Rotate about | Axis |
|---|---|
| X-Axis | 1.0 0.0 0.0 |
| Y-Axis | 0.0 1.0 0.0 |
| Z-Axis | 0.0 0.0 1.0 |
| Any Axis | 0.0 0.0 0.0 |
A sample billboard group
XML Encoding
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<!-- Y-axis --> <Billboard axisOfRotation='0.0 1.0 0.0'> <Shape><!-- ... --></Shape> <Shape><!-- ... --></Shape> <Shape><!-- ... --></Shape> <!-- ... --> </Billboard> |
Classic Encoding
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Billboard { # Y-axis axisOfRotation 0.0 1.0 0.0 children [ Shape { ... } Shape { ... } Shape { ... } ... ] } |
Syntax: Anchor
An Anchor node creates a group that acts as a clickable anchor
- Every child node in the group is displayed
- Clicking any child follows a URL
- A description names the anchor
XML Encoding
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<Anchor url='"stairwy.wrl"' description='Twisty Stairs'> <!-- children ... --> </Anchor> |
Classic Encoding
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Anchor { url "stairwy.wrl" description "Twisty Stairs" children [ ... ] } |
Syntax: Inline
An Inline node creates a special group from another X3D file's contents
- Children read from file selected by a URL
- Every child node in group is displayed
XML Encoding
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<Inline url='"table.wrl"'/> |
Classic Encoding
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Inline { url "table.wrl" } |
Summary
- The Group node creates a basic group
- The Switch node creates a group with 1 choice used
- The Transform node creates a group with a new coordinate system
- The Billboard node creates a group with a coordinate system that rotates to face the viewer
- The Anchor node creates a clickable group
- Clicking any child in the group loads a URL
- The Inline node creates a special group loaded from another X3D file