Open Inventor

1
Open Inventor

• A short introduction

2
Capabilities of Open Inventor

• Easy construction of 3D scenes
• User interaction
• Animation

3
Overview

• Open Inventor is a scenegraph graphics API All
  visible objects are stored in a scenegraph
• Built on top of OpenGL

4
Scenegraph Anatomy

• There are three kinds of nodes
• Group nodes allow construction of trees
• Property nodes change the color / location / ...
  of the next object
• Shapes visible objects

5
Common node types

• Group nodes
• SoGroup ? SoSeparator, SoSwitch, ...
• Property nodes
• Transform SoTransform, SoRotation, ...
• Appearance SoMaterial, SoDrawStyle, ...
• Shape nodes
• SoShape ? SoCone, SoCube, SoText2, ...

6
Scene objects

• class name prefix So (scene object)
• derived from SoNode
• can be inserted directly into the scenegraph
• Example
• root-gtaddChild(new SoSphere)

7
Fields

• class name prefix SoSF/SoMF (Single
  Field/Multiple Field)
• public attributes of Scene objects
• specify the appearance of scene objects (like
  radius, height, color ...)

8
... Fields

• Newly created scene Objects have fields with
  default values
• Fields can be connected to other fields
• Fields can be changed using setValue(s)
• Example
• SoSphere sphere new SoSphere
• ...
• sphere-gtradius.setValue(3)

9
Typical Open Inventor code

• ...
• SoSeparator root new SoSeparator
• SoTranslation t new SoTranslation
• t-gttranslation.setValue(2, 0, 0)
• root-gtaddChild(t)
• root-gtaddChild(new SoCube)
• ...

10
Loading Scenes

• Loading scenes is very easy
• SoInput scene
• scene.openFile("chessboard.iv")
• root SoDBreadAll(scene)

11
Advanced Topics

• Manipulators allow the user to modify the scene
• Actions compute bounding boxes, picks objects ...
• Sensors can detect changes in the scene and
  invoke callback functions
• Engines can animate the scene

12
A few tips...

• Follow the setup tutorial for Coin3D!
• You need a new So... class? You need a new
  include statement!
• Dont forget to insert your nodes into the scene
  graph!

13
Resources

• Coin3D A free implementation of Open Inventor
  www.coin3d.org
• Inventor Mentor A good online reference book
• Another presentation http//vrlab.postech.ac.kr/v
  r/gallery/edu/vr/openinventor.ppt
• dev-gallery Some simple tutorials
  www.dev-gallery.com/programming/openInventor/main.
  html