Class SoCircularExtrusion
- All Implemented Interfaces:
SafeDisposable
SoCircularExtrusion
node is a geometric shape based on a constant radius
circle cross section extruded along a three-dimensional polyline (spine). The circle center lies on the spine and the circle lies on the plane normal to the spine at each point. This is similar to specifying an SoExtrusion
with a circle cross-section, which is convenient for many applications, but this node has additional advantages because it responds to the SoComplexity
value.
The application can specify which caps are created using the fields beginCap
and endCap
. By default both caps are visible.
The application can specify the visible portion of the shape along the spine using normalized curvilinear coordinates (activeSection). By default the entire spine is visible.
The SoCircularExtrusion
representation is dependent on SoComplexity.value
. The shape is always simplified when the SoComplexity
value is less than 1. Both the cross section (number of segments used for the circle) and the spine (number of points used for the spine) are affected by the simplification. The simplification algorithm approximates the spine by taking into account its curvature. The cross section circle is approximated by at least 10 points. With a SoComplexity
value of 0 the extruded shape has the roughest representation.
Approximately the same geometry could be defined using an SoExtrusion
node, but that node does not currently respond the SoComplexity
value. Likewise the clipping behavior could be obtained using two SoClipPlane
nodes, but SoCircularExtrusion
uses less memory when the activeSection is a subset of the full spine. These two features make SoCircularExtrusion
valuable when a large number of cylindrical objects must be displayed.
The scaleMode
field (inherited from SoBaseExtrusion
) is used to select the points that will be scaled by the current transformation (for example SoTransform
), 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 non-uniform.
- SECTION_ONLY : Only the cross section points are scaled. Not currently implemented.
- NONE :
SoExtrusion
ignores the scaling state. Not currently implemented.
The extrusionMode
field (inherited from SoBaseExtrusion
) is used to select the extrusion algorithm.
Limitations:
The spine polyline segments must be C0 continous, that is, the spine must be connected at joints. The following segments may be C1 discontinous but be aware that very narrow angles between consecutive polyline semgments can produce odd results with SMOOTH extrusionMode
modes. This is especially noticeable when the angles between segments are very small with respect to the radius
. In the following images the consecutive points A, B, C in the spine show one of these cases. The problem is at point B whose cross sections are abnormally large.
Spine | Wireframe | Shaded |
![]() | ![]() | ![]() |
- Since:
- Open Inventor 8.6
File format/default:
CircularExtrusion {
beginCap true endCap true spine [ 0 0 0, 0 1 0 ] scaleMode DEFAULT extrusionMode SMOOTH radius [ 1 ] activeSection [ 0, 1 ] - See Also:
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Nested Class Summary
Nested ClassesNested 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
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Field Summary
FieldsModifier and TypeFieldDescriptionfinal SoSFVec2f
Defines the visible section of the spine in normalized coordinates.final SoSFFloat
Radius of the circular cross-section.Defines the spine simplification behavior of the extrusion.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
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Constructor Summary
Constructors -
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
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Field Details
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radius
Radius of the circular cross-section. The default value is 1. -
activeSection
Defines the visible section of the spine in normalized coordinates. The default is (0,1) meaning that the entire spine is rendered. -
spineSimplificationMode
Defines the spine simplification behavior of the extrusion. . Default is DEFAULT. DEFAULT means spine simplification depends only on geometry. This is appropriate in the typical case where a single material is applied to the entire extrusion. RESPECT_MATERIALS means spine simplification preserves multiple materials (if any) applied to the extrusion. This could reduce rendering performance.
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Constructor Details
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SoCircularExtrusion
public SoCircularExtrusion()Constructor.
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