© TMC Computer School HC20203 VRML 3 - 1 HIGHER DIPLOMA IN COMPUTING Chapter 3 – Object Definition in VRML

© TMC Computer School

HC20203 VRML 3 - 1

HIGHER DIPLOMA IN COMPUTING

Chapter 3 – Object Definition in VRML


HC20203 VRML 3 - 2


Building Primitive Shapes

Each node may have the following characteristics A type name. Examples include Box, Color, Group,

Sphere, Sound, or SpotLight Zero or more fields that define how each node

differs from other nodes of the same type A set of events that it can receive and send An implementation A name

The Shape node associates a geometry node with nodes that define that geometry's appearance


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Building Primitive Shapes

Shape nodes must be part of the transformation hierarchy to have any visible result

The transformation hierarchy must contain Shape nodes for any geometry to be visible

A Shape node contains exactly one geometry node in its geometry field

The appearance of a shape is being described y the Appearance and Material nodes

Using the default values, we will be able to create shaded white shape

These primitive shapes include Box, Cone, Cylinder and Sphere node


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The Shape Syntax

All VRML shapes are built using the Shape node. The syntax of Shape node is as follows:

Shape {

appearance NULL # exposedfield SFNodegeometry NULL # exposedField SFNode

} The value of the geometry field specifies either a Box,

Cone, Cylinder, and Sphere nodes The default NULL value for this field indicates the

absence of geometry


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The Shape Syntax

The appearance field specifies a node defining the appearance of the shape including its color and surface texture

The default NULL indicates a glowing white appearance


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The Appearance and Material Node

The Material node specifies material attributes as follows: Material{

ambientIntensity 0.2 # exposedfield SFFloatdiffuseColor 0.8 0.8 0.8 # exposedField SFColoremissiveColor 0.0 0.0 0.0 # exposedField SFColorshininess 0.2 # exposedField SFFloatspecularColor 0.0 0.0 0.0 # exposedField SFColor transparency 0.0 # exposedField SFFloat

}


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The Appearance and Material Node

The Appearance node specifies appearance attributes as follows:

Appearance{

material NULL # exposedfield SFNodetexture NULL # exposedField SFNodetextureTransform NULL # exposedField SFNode

} Note that the default values for the Material node create

shaded white shapes


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The Cone Node

The Cone node creates a cone-shaped primitive geometry and may be used as the value of the geometry field in the Shape node

Cone{

bottomRadius 1.0 # field SFFloatheight 2.0 # field SFFloatside TRUE # field SFBoolbottom TRUE # field SFBool

}


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The Cone Node

The value of the bottomRadius specifies the radius of the bottom of a 3D cone centered at the origin

The height specifies the cone’s height in the Y direction

The side specifies whether or not the sloping sides of the once are built

The bottom specifies whether or not the circular bottom of the cone is built


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The Cylinder Node

The Cylinder node creates a cylinder-shaped primitive geometry and may be used as the value of the geometry field in the Shape node

Cylinder {radius 1.0 # field SFFloatheight 2.0 # field SFFloatside TRUE # field SFBooltop TRUE # fieldSFBoolbottom TRUE # field SFBool

}


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The Cylinder Node

The value of the radius specifies the radius of 3D cylinder centered at the origin

The height specifies the cylinder’s height in the Y direction

The side specifies whether or not the curving sides of the cylinder are built

The top specifies whether or not the circular top of the cylinder is built

The bottom specifies whether or not the circular bottom of the cylinder is built


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The Sphere Node

The Sphere node creates a sphere-shaped (a ball or globe) primitive geometry and may be used as the value of the geometry field in the Shape node

Sphere

{

radius 1.0 # field SFFloat

}

The value of the radius specifies the radius of the 3D sphere centered at the origin


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The Group Node

The Group node is used to group VRML nodes together Group{

children [ ] # exposedField MFNodebboxCenter 0.0 0.0 0.0 # field SFVec3fbboxSize -1.0 -1.0 -1.0 # field SFVec3faddChildren # eventIn MFNoderemoveChildren # eventOut MFNode

} The value of the children field specifies a list of child nodes to be

included in the group. Typical children field include Shape nodes and other Group nodes. In this course, we will not be covering the rest of the fields


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Default Box

#VRML V2.0 utf8

Shape {

appearance Appearance {

material Material { }

}

}


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Box with Dimension

#VRML V2.0 utf8

Shape {



}

geometry Box {

size 1.0 3.0 5.0

}

}


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Default Cone

#VRML V2.0 utf8

Shape {



}

geometry Cone { }

}


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Cone with Dimension

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Cone { bottomRadius 3.5 height 1.5 }}


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Default Cylinder

#VRML V2.0 utf8

Shape {



}

geometry Cylinder { }

}


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Cylinder with Dimension

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Cylinder { radius 4.0 height 1.0 }}


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Cylinder with no Top and Bottom

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Cylinder { radius 4.0 height 1.0 top FALSE bottom FALSE }}


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Default Sphere

#VRML V2.0 utf8

Shape {



}

geometry Sphere { }

}


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3D Plus Sign

#VRML V2.0 utf8Group { children [ Shape { appearance DEF White Appearance { material Material { } } geometry Box { size 25.0 2.0 2.0 } },


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3D Plus Sign

Shape { appearance USE White geometry Box { size 2.0 25.0 2.0 } }, Shape { appearance USE White geometry Box { size 2.0 2.0 25.0 } } ]}


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A Space Station

#VRML V2.0 utf8Group { children [ Shape { appearance DEF White Appearance { material Material { } } geometry Box { size 10.0 10.0 10.0 } },


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A Space Station Shape {

appearance USE White geometry Sphere { radius 7.0 } }, Shape { appearance USE White geometry Cylinder { radius 12.5 height 0.5 } },


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A Space Station

Shape { appearance USE White geometry Cylinder { radius 4.0 height 20.0 } }, Shape { appearance USE White geometry Cylinder { radius 3.0 height 30.0 } },


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A Space Station

Shape {

appearance USE White

geometry Cylinder {

radius 1.0

height 60.0

}

}

]

}


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Building Text Shapes

In order to build text node in VRML, we need to specify the VRML Text node as the value of the Shape node’s geometry field

For each of the text geometry, we can specify a list of text strings and the length of each string

The FontStyle node aids us in controlling the font, style and size of the text


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Fields in the Text node enable us to control: the text string or series of characters to be built the maximum permissible extent of the lines or

columns of text the exact length of each line or column of text the font or typeface to use for the text along with its

style, justification, and other attributes


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The FontStyle node enables us to control: the font family defining the character shapes used for

the text the font style of the text such as bold, italic or normal the font size of the text the spacing of the text lines or columns the justification of the lines or columns of text the orientation of the text: horizontal or vertical the flow direction of the text: from left to right, right to

left, top to bottom or bottom to top the specific language features to use


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The Text Node

The Text node is used to create text geometry and may be used as the value for the geometry field in s Shape node

Text{

string [ ] # exposedField MFStringlength [ ] # exposedField MFFloatmaxExtent 0.0 # exposedField SFFloatfontStyle NULL # exposedField SFNode

} The value of the string exposed field specifies one more or lines

of text to build Each line or column of text is enclosed within quotation mark


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The Text Node

The value of string exposed field can be changed by routing an event to the exposed field’s implied set_string eventIn

The value of the length exposed field specifies the desired length, in VRML units of each line of text

A length of 0.0 specifies text strings that are built at their natural length without compressing or expanding

The value of the maxExtent specifies the maximum permissible length in VRML units of any line of column of text

And the value of fontStyle specifies the characteristics defining the look of the text created by the Text node


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The FontStyle Node The FontStyle node is used to control the look of the text geometry created by a

Text node A FontStyle node may be used as the value of the fontStyle field in a Text node

FontStyle{

family “SERIF” # field SFStringstyle “PLAIN” # field SFStringsize 1.0 # field SFFloatspacing 1.0 # field SFFloatjustify “BEGIN” # field SFStringhorizontal TRUE # field SFBoolleftToRight TRUE # field SFBooltopToBottom TRUE # field SFBoollanguage “” # field SFString

}


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The FontStyle Node

The value of the family field specifies the standard VRML font families to use and the valid font includes: “SERIF” “SANS” “TYPEWRITER”

The value of the style field specifies the text style to use and the valid style includes: “PLAIN” “BOLD” “ITALICS” “BOLDITALIC”


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The FontStyle Node

The value of the size field specifies the height of the characters measured in VRML units

The value of the spacing field specifies the vertical line spacing in VRML unit of horizontal text or the horizontal column spacing of the vertical text

The value of the horizontal field specifies whether text strings are built horizontally or vertically

The values of horizontal, leftToRight and topToBottom fields are used in combination to control horizontal or vertical text placement


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The FontStyle Node

The values of justify field specifies the way in which the text shape’s block of text is positioned relative to the X and Y axes “FIRST” “BEGIN” “MIDDLE” “END”

The value of the language field specifies the context of the language used in values of he Text node’s string field


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A Text Shape

#VRML V2.0 utf8

Shape {



}

geometry Text {

string "Qwerty"

}

}


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A List of Text String

#VRML V2.0 utf8

Shape {



}

geometry Text {

string [ "Qwerty", "0123" ]

}

}


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Small Length Field Value

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string "Qwerty" length 2.0 }}


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A List of Text String

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string [ "Qwerty", “Qwerty” ] length [ 3.0, 4.0 ] }}


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Text Limited by Maximum Extent

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string [ "Qwerty Uiop", "Asdf" ] maxExtent 4.0 }}


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Using Plain Font#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string "Qwerty" fontStyle FontStyle { family "SERIF" style "" } }}


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Using Bold Font#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string "Qwerty" fontStyle FontStyle { family "SERIF" style "BOLD" } }}


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Using Small Font Text

#VRML V2.0 utf8

Shape {



}

geometry Text {

string "Qwerty"

fontStyle FontStyle {

size 0.5

}

}


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Text with more than Default Spacing

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string [ "Qwerty", "0123" ] fontStyle FontStyle { spacing 2.0 } }}


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Text with less than Default Spacing

#VRML V2.0 utf8Shape { appearance Appearance { material Material { } } geometry Text { string [ "Qwerty", "0123" ] fontStyle FontStyle { spacing 0.5 } }}


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Two Text Shape with Different Justification

#VRML V2.0 utf8Group { children [ Shape { appearance DEF White Appearance { material Material { } } geometry Text { string "First" fontStyle FontStyle { family "SERIF" style "ITALIC" justify "END" size 1.0


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Two Text Shape with Different Justification

Shape { appearance USE White geometry Text { string "Second" fontStyle FontStyle { family "SANS" style "BOLD" justify "BEGIN" size 1.0 } } } ]}


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Two Text with a Line Between Them

#VRML V2.0 utf8Group { children [ Shape { appearance DEF White Appearance { material Material { } } geometry Text { string [ "Above", "Below" ] fontStyle FontStyle { justify "MIDDLE" } } },


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Two Text with a Line Between Them

Shape {


geometry Box {

size 5.0 0.01 2.0

}

}

]

}


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Using DEF and USE to share Font Properties

#VRML V2.0 utf8Group { children [ Shape { appearance DEF White Appearance { material Material { } } geometry Text { string [ "Over", "Strike" ] fontStyle DEF myFontStyle FontStyle { size 6.0 family "TYPEWRITER" justify "MIDDLE" } } },


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Using DEF and USE to share Font Properties

Shape {


geometry Text {

string [ "----", "------" ]

fontStyle USE myFontStyle

}

}

]

}

Documents

© TMC Computer School HC20203 VRML 3 - 1 HIGHER DIPLOMA IN COMPUTING Chapter 3 – Object Definition in VRML