4. Example Content

Click above for the Lunatic Knight Nurbs: For best results, use the dynamic tessellation mode.

What is a NURB?

NurbsCurve - The boxes represent the ControlPoints of the curve, which define the shape of the curve. While a conventional primitive is defined by a large amount of points on the  curve itself, the NurbsCurve needs only the small amount of ControlPoints and a few other parameters.

Low Download Size

These samples demonstrate the space savings that can be attained by using NURBS to represent complex shapes. The files are not compressed. The IndexedFaceSet versions contain coordinate, texture coordinate and coordIndex information, but not the better-quality normals computed directly from the NURBS surface.

• Duck stored as NURBS - 11KB
• Duck stored as low-medium resolution IndexedFaceSet : 179 K - 4374 triangles
• Duck stored as medium-resolution IndexedFaceSet : 469 K - 11070 triangles
• Duck stored as high-resolution IndexedFaceSet : 2.2 M - 50598 triangles

NURBS And Animation

Simple animations, performed by modifying a single control point from javascript:

• Animated 2x2 surface
• Animated 3x3 surface
• Animated 4x4 surface
• Flying Birds

Animation using a CoordinateInterpolator:

• NURBS version, controlPoints are animated
• Standard version, coordinates of a mesh are animated

• Venus - NURBS deformation on coordinates of IndexedFaceSet The Shape is enclosed in a grid box, only the grid points are animated.
• Sphere - NURBS deformation on controlPoints of a NurbsSurface

LOD - Level Of Detail

LOD examples, use these to view the effects of different tessellation mode settings, especially the first example. Note the dynamic tessellation as you move near the objects.

• Colony City plaza crowded with flock of NURBS ducks - a dynamic tessellation stress test
• LOD Test with Okupi Bouncer - a dynamic tessellation stress test with several instances of the same NURBS model, ordered by distance
• 4 Ducks
• 4 Ducks & a head

Perfect Smoothness

This demo should show you what NURBS can do in comparision to a polygon based model. Typically when you zoom in closer to a 3D object based on a polygon model, the models gets sooner or later edgy, because the you move so close to the object that you can actually see the polygon. Since we're using NURBS (a mathematical description of the surface), not only the file size get's smaller, but also the acuraccy is better, because with each step you move closer to the object the VRML/NURBS Plugin can again tessalate the surface again with an resolution that the human eye can't see the resulotion. With this method so call Level of Detail can easily be achieved, because you only have one model, but you tessalate only as much as it is necessary. In polygon based 3D models you would have to have several 3D models for each level of detail you want to display.

Zoom to the Knight Nurbs Avatar - By using 'pageup' you can jump between the various Viewpoints. Please press 'pageup' 3 times and you can see that there is no difference, regardless how close you ge to the Avatar.

Okupi Avatars

Okupi NURBS Avatars

Models

The examples below have been exported from 3D Studio Max example data sets using the VRML NURBS exporter. The source code is headed by a EXTERNPROTO definition. In this PROTO a IndexLineSet model of the the NurbsSurface is computed if the browser (others than BS Contact 4.2) does not support the new nodes.

• Head
• Another head
• Perfume bottle
• Stingray
• Duck
• Pumpkin

TIP: If you want to see the wire frame model formed by the control vertices, deactivate the urn-field in the EXTERNPROTO definition:

 ### "urn:inet:bitmanagement.de:node:NurbsSurface"

Thus you can also check what a model will look like in other browsers. Have a look at the Head shown as wire frame.

X3D Examples

The examples are from Charles Adams below have been created in Maya. The native Ccontact urn was added to the files and the extra field closedSurface was removed.

• Fred The Bunny
• Animated Surface Head