Class SoExtrusion
 java.lang.Object

 All Implemented Interfaces:
SafeDisposable
public class SoExtrusion extends SoBaseExtrusion
Geometric shape formed by extruding a 2D cross section along a 3D spine. TheSoExtrusion
node specifies geometric shapes based on a twodimensional cross section extruded along a threedimensional spine. The cross section can be scaled and rotated at each spine point to produce a wide variety of shapes.An
SoExtrusion
is defined by:crossSection
The shape that will be extruded, defined by a 2D piecewise linear curve in the XZ plane (described as a series of connected vertices).spine
The crosssection is extruded along this path, defined by a 3D piecewise linear curve (described as a series of connected vertices). This field is inherited from the parent classSoBaseExtrusion
.scale
values
The crosssection curve is scaled by this value on the X and Z axes. If one value is specified it applies to every spine point, else there should be as many values as there are points in the spine. All scale values must be > 0.orientation
values, The crosssection curve is rotated by this value relative to a local reference system with origin at the current spine point and X / Z axes in the plane containing the crosssection curve. If one value is specified it applies to every spine point, else there should be as many values as there are points in the spine.
Shapes are constructed as follows  For each point in the spine, the crosssection curve, which is a curve in the XZ plane, is scaled about the origin by the corresponding
scale
parameter (first value scales in X, second value scales in Z), rotated about the origin by the correspondingorientation
parameter and translated by the vector defined by the corresponding vertex of thespine
curve. Each instance of the crosssection is then connected to the following instance.The
scaleMode
field is used to select the points that will be scaled by the current transformation (for exampleSoTransform
), if any. Translation and rotation are applied in all cases. The options are: DEFAULT : Every point in the generated geometry is scaled.
 SPINE_ONLY : Only the spine points are scaled. The cross section points are not scaled, so the cross section shape is undistorted even is scaling is nonuniform.
 SECTION_ONLY : Only the cross section points are scaled. Not currently implemented.
 NONE :
SoExtrusion
ignores the scaling state. Not currently implemented.
A transformed cross section is found for each joint (that is, at each vertex of the
spine
curve, where segments of the extrusion connect), and the joints and segments are connected to form the surface. No check is made for selfpenetration. Each transformed cross section is determined as follows:1. Start with the cross section as specified, in the XZ plane.
2. Scale it about (0, 0, 0) by the value for
scale
given for the current joint.3. Apply a rotation so that when the cross section is placed at its proper location on the spine it will be oriented properly. Essentially, this means that the cross section's Y axis ( up vector coming out of the cross section) is rotated to align with an approximate tangent to the spine curve.
For all points other than the first or last: The tangent for
spine
[ i ] is found by normalizing the vector defined by (spine
[ i +1] spine
[ i 1]).If the spine curve is closed: The first and last points need to have the same tangent. This tangent is found as above, but using the points
spine
[0] forspine
[ i ],spine
[1] forspine
[ i +1] andspine
[ n 2] forspine
[ i 1], wherespine
[ n 2] is the next to last point on the curve. The last point in the curve,spine
[ n 1], is the same as the first,spine
[0].If the spine curve is not closed: The tangent used for the first point is just the direction from
spine
[0] tospine
[1], and the tangent used for the last is the direction fromspine
[ n 2] tospine
[ n 1].In the simple case where the spine curve is flat in the XY plane, these rotations are all just rotations about the Z axis. In the more general case where the spine curve is any 3D curve, you need to find the destinations for all 3 of the local X, Y, and Z axes so you can completely specify the rotation. The Z axis is found by taking the cross product of:
(
spine
[ i 1] spine
[ i ]) and (spine
[ i +1] spine
[ i ]).If the three points are collinear then this value is zero, so take the value from the previous point. Once you have the Z axis (from the cross product) and the Y axis (from the approximate tangent), calculate the X axis as the cross product of the Y and Z axes.
4. Given the plane computed in step 3, apply the
orientation
to the crosssection relative to this new plane. Rotate it counterclockwise about the axis and by the angle specified in theorientation
field at that joint.5. Finally, the cross section is translated to the location of the
spine
point.
Surfaces of revolution: If the cross section is an approximation of a circle and the spine is straight, then the
SoExtrusion
is equivalent to a surface of revolution, where thescale
parameters define the size of the cross section along the spine.Cookiecutter extrusions: If the scale is 1, 1 and the spine is straight, then the cross section acts like a cookie cutter, with the thickness of the cookie equal to the length of the spine.
Bend/twist/taper objects: These shapes are the result of using all fields. The spine curve bends the extruded shape defined by the cross section, the orientation parameters twist it around the spine, and the scale parameters taper it (by scaling about the spine).
SoExtrusion
has three parts: the sides, thebeginCap
(the surface at the initial end of the spine) and theendCap
(the surface at the final end of the spine). The caps have an associated SFBool field that indicates whether it exists (true) or doesn't exist (false).When the
beginCap
orendCap
fields are specified as true, planar cap surfaces will be generated regardless of whether thecrossSection
is a closed curve. (IfcrossSection
isn't a closed curve, the caps are generated as if it wereequivalent to adding a final point to crossSection
that's equal to the initial point. Note that an open surface can still have a cap, resulting (for a simple case) in a shape something like a soda can sliced in half vertically.) These surfaces are generated even ifspine
is also a closed curve. If a field value is false, the corresponding cap is not generated.SoExtrusion
automatically generates its own normals. Orientation of the normals is determined by the vertex ordering of the quads generated bySoExtrusion
. The vertex ordering is in turn determined by thecrossSection
curve. If thecrossSection
is counterclockwise when viewed from the +Y axis, then the polygons will have counterclockwise ordering when viewed from 'outside' of the shape (and vice versa for clockwise orderedcrossSection
curves).Texture coordinates are automatically generated by extrusions. Textures are mapped so that the coordinates range in the U direction from 0 to 1 along the
crossSection
curve (with 0 corresponding to the first point incrossSection
and 1 to the last) and in the V direction from 0 to 1 along thespine
curve (again with 0 corresponding to the first listedspine
point and 1 to the last). WhencrossSection
is closed, the texture has a seam that follows the line traced by thecrossSection
's start/end point as it travels along thespine
. If theendCap
and/orbeginCap
exist, thecrossSection
curve is uniformly scaled and translated so that the largest dimension of the crosssection (X or Z) produces texture coordinates that range from 0.0 to 1.0. ThebeginCap
andendCap
textures' S and T directions correspond to the X and Z directions in which thecrossSection
coordinates are defined.Also 3D texture coordinates are automatically generated, in a similar way to 2D textures.
NOTE: If your extrusion appears to twist unexpectedly, try setting environment variable OIV_EXTRUSION_EPSILON to a value slightly smaller number than the default, which is .998.
NOTE: If your
crossSection
is not convex, you must use aSoShapeHints
and set the faceType field to UNKNOWN_FACE_TYPE.File format/default:
Extrusion {
beginCap true endCap true spine [ 0 0 0, 0 1 0 ] scaleMode DEFAULT crossSection [ 1 1, 1 1, 1 1, 1 1, 1 1 ] orientation 0 0 1 0 scale 1 1  See Also:
SoBaseExtrusion


Nested Class Summary

Nested classes/interfaces inherited from class com.openinventor.inventor.nodes.SoBaseExtrusion
SoBaseExtrusion.ExtrusionModes, SoBaseExtrusion.ScaleModes

Nested classes/interfaces inherited from class com.openinventor.inventor.nodes.SoShape
SoShape.ShapeTypes

Nested classes/interfaces inherited from class com.openinventor.inventor.nodes.SoNode
SoNode.RenderModes

Nested classes/interfaces inherited from class com.openinventor.inventor.Inventor
Inventor.ConstructorCommand


Field Summary
Fields Modifier and Type Field Description SoMFVec2f
crossSection
The shape that will be extruded, defined by a 2D piecewise linear curve in the XZ plane (described as a series of connected vertices).SoMFRotation
orientation
The crosssection curve is rotated by this value relative to a local reference system with origin at the current spine point and X / Z axes in the plane containing the crosssection curve.SoMFVec2f
scale
The crosssection curve is scaled by this value on the X and Z axes.
Fields inherited from class com.openinventor.inventor.nodes.SoBaseExtrusion
beginCap, endCap, extrusionMode, scaleMode, spine

Fields inherited from class com.openinventor.inventor.nodes.SoShape
boundingBoxIgnoring

Fields inherited from class com.openinventor.inventor.Inventor
VERBOSE_LEVEL, ZeroHandle


Constructor Summary
Constructors Constructor Description SoExtrusion()
Constructor.

Method Summary

Methods inherited from class com.openinventor.inventor.nodes.SoShape
getShapeType, isPrimitiveRestartAvailable, isPrimitiveRestartAvailable

Methods inherited from class com.openinventor.inventor.nodes.SoNode
affectsState, callback, copy, copy, distribute, doAction, getAlternateRep, getBoundingBox, getByName, getMatrix, getPrimitiveCount, getRenderEngineMode, getRenderUnitID, GLRender, GLRenderBelowPath, GLRenderInPath, GLRenderOffPath, grabEventsCleanup, grabEventsSetup, handleEvent, isBoundingBoxIgnoring, isOverride, pick, rayPick, search, setOverride, touch, write

Methods inherited from class com.openinventor.inventor.fields.SoFieldContainer
copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults

Methods inherited from class com.openinventor.inventor.misc.SoBase
dispose, getName, isDisposable, isSynchronizable, setName, setSynchronizable

Methods inherited from class com.openinventor.inventor.Inventor
getNativeResourceHandle




Field Detail

crossSection
public final SoMFVec2f crossSection
The shape that will be extruded, defined by a 2D piecewise linear curve in the XZ plane (described as a series of connected vertices). Default is a square [ 1 1, 1 1, 1 1, 1 1, 1 1 ].

orientation
public final SoMFRotation orientation
The crosssection curve is rotated by this value relative to a local reference system with origin at the current spine point and X / Z axes in the plane containing the crosssection curve. If one value is specified it applies to every spine point, else there should be as many values as there are points in the spine. Default is no rotation.

scale
public final SoMFVec2f scale
The crosssection curve is scaled by this value on the X and Z axes. If one value is specified it applies to every spine point, else there should be as many values as there are points in the spine. All scale values must be > 0. Default is (1,1) meaning no scaling.

