Motivation

Extruded shapes are very common

• Tubes, pipes, bars, vases, donuts
• Other tricky uses...

How can you do it:

• You can build extruded shapes using an IndexedFaceSet node.
• You can build extruded shapes more easily and efficiently using an Extrusion node.

Creating extruded shapes

Extruded shapes are described by:

• A 2-D cross-section
• A 3-D spine along which to sweep the cross-section

Extruded shapes are like long bubbles created with a bubble wand:

• The bubble wand's outline is the cross-section
• The path along which you swing the wand is the spine

Syntax: Extrusion

An Extrusion geometry node creates extruded geometry:

• crossSection - 2-D cross-section
• spine - 3-D sweep path
• endCap and beginCap - cap ends

An Extrusion geometry node creates extruded geometry:

• solid - shape is solid
• ccw - faces are counter-clockwise
• convex - faces are convex

Squishing and twisting extruded shapes

You can scale the cross-section along the spine:

• Vases, musical instruments
• Surfaces of revolution

You can rotate the cross-section along the spine

• Twisting ribbons

Syntax: Extrusion

An Extrusion geometry node creates geometry using:

• scale - cross-section scaling per spine point
• orientation - cross-section rotation per spine point

Summary

• An Extrusion node efficiently creates extruded shapes
• The crossSection field specifies the cross-section
• The spine field specifies the sweep path
• The scale and orientation fields specify scaling and rotation at each spine point