VRML 97 Geometry

Computer Graphics Group
Geometry: 10 nodes
VRML 97
• Children of Shape nodes (field: geometry)
• Boundary representation only
Department of Computer Science and Engineering
http://www.cgg.cvut.cz
Building Static Worlds
• Geometry
• Grouping & Transformations
• Colors
Box
Cone
Cylinder
+/-cap
+/-caps
Sphere
• Undetermined number of facets
• Back faces never generated
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VRML 97 - Static worlds
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Geometry (contd.)
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The most sophisticated node
IndexedFaceSet
coord
IndexedFaceSet IndexedLineSet
PointSet
Coordinate
point
Normal
vector
Color
color
TextureCoordinate
point
normal
color
texCoord
Extrusion
ElevationGrid
Text
coordIndex, normalIndex, colorIndex, texCoordIndex
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IndexedFaceSet - other params.
colorPerVertex
normalPerVertex
convex
ccw
solid
creaseAngle
TRUE
TRUE
TRUE
TRUE
TRUE
0
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Extrusion … 2,5D
crossSection [1
-1
1, 1 -1, -1 -1,
1, 1 1]
# profile, stencil, contour
spine
[0 0 0, 0 1 0]
# trajectory
scale
orientation
[1 1] # for each section
[0 0 1 0]
#
dtto
beginCap, endCap, convex, ccw, solid, creaseAngle
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1
Extrusion - example
ElevationGrid
0
0
1.0
1.0
[]
xDimension
zDimension
xSpacing
zSpacing
height
# number of columns
# number of rows
# array of heights
color, normal, texCoord ... SFNode
colorPerVertex, normalPerVertex,
ccw, solid, creaseAngle
crossSection: 8 points, spine: 8 points
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Jiří Žára
VRML 97 - Static worlds
Making scene graph - group nodes
8
Group
Group
container for nodes
children
[]
Transform
dtto + transformation
Shape
container for one object
bboxSize
bboxCenter
-1 -1 –1 # hint to browser
0 0 0
# hint to browser
(geometry + appearance)
Inline
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container for external file
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VRML 97 - Static worlds
Transform
scale
scaleOrientation
rotation
center
translation
10
Shape
# 1st transf.
Group, Transform
# rotation before scaling
# rotation (2nd transf.)
children
Shape
# pivot point for rotation
...
# 3rd transf.
appearance
Appearance
geometry
Box, Cone, ...
For different order of transformations use graph
hierarchy.
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VRML 97 - Static worlds
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2
Inline
Colors
url
[] # list of URLs
bboxSize
bboxCenter
-1 -1 –1 # hint to browser
0 0 0
# hint to browser
• One color for the whole object
Material { }
A child of Appearance node.
• Individual colors per faces/vertices
First successful URL will be used
Color { }
For IndexedFaceSet, IndexedLineSet,
PointSet, and ElevationGrid.
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Material: Phong shading coeffs.
ambientIntensity
diffuseColor
specularColor
shininess
emissiveColor
transparency
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End of this part
0.2
0.8 0.8 0.8
0 0 0
0.2
0 0 0
0
• Set as many as possible parameters to zeros
• Utilize DEF & USE statements
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3