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SoFenceSlice Class

Fence slice shape node.

Inheritance Hierarchy

Namespace: OIV.VolumeViz.Nodes
Assembly: OIV.VolumeViz (in OIV.VolumeViz.dll) Version: 2024.2.0.0 (2024.2.0)
Syntax
public class SoFenceSlice : SoSlice

The SoFenceSlice type exposes the following members.

Constructors
  NameDescription
Public methodSoFenceSlice

Constructor.

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Methods
  NameDescription
Public methodAffectsState

Overrides default method on OIV.Inventor.Nodes.SoNode.

(Inherited from SoShape.)
Public methodBeginShape(SoAction, SoShapeTriangleShapes)
Calls BeginShape(action, shapeType, (OIV.Inventor.Details.SoFaceDetail ^)nullptr).
(Inherited from SoShape.)
Public methodBeginShape(SoAction, SoShapeTriangleShapes, SoFaceDetail)

These methods can be used by subclasses to generate triangles more easily when those triangles are part of a larger structure, such as a triangle strip, triangle fan, or triangulated polygon, according to the TriangleShape enumerated type.

(Inherited from SoShape.)
Public methodCallback

Implements primitive generation for all shapes.

(Overrides SoShapeCallback(SoCallbackAction).)
Public methodComputeBBox(SoAction, SbBox3f, SbVec3f)

Compute the bounding box.

(Overrides SoVolumeShapeComputeBBox(SoAction, SbBox3f, SbVec3f).)
Public methodComputeBBox(SoAction, SbXfBox3d, SbVec3d)

Compute object oriented bounding box (OOB) for subclass using information in the given action (which may not necessarily be an OIV.Inventor.Actions.SoGetBoundingBoxAction).

(Overrides SoShapeComputeBBox(SoAction, SbXfBox3d, SbVec3d).)
Public methodCopy
Calls Copy(false).
(Inherited from SoNode.)
Public methodCopy(Boolean)

Creates and returns an exact copy of the node.

(Inherited from SoNode.)
Public methodCopyFieldValues(SoFieldContainer)
Calls CopyFieldValues(fc, false).
(Inherited from SoFieldContainer.)
Public methodCopyFieldValues(SoFieldContainer, Boolean)

Copies the contents of fc's fields into this object's fields.

(Inherited from SoFieldContainer.)
Public methodDispose
Releases all resources used by SoDisposable.
(Inherited from SoDisposable.)
Public methodDistribute
(Inherited from SoNode.)
Public methodDoAction
Public methodEnableNotify

Notification at this Field Container is enabled (if flag == true) or disabled (if flag == false).

(Inherited from SoFieldContainer.)
Public methodEndShape

end shape previously started with OIV.Inventor.Nodes.SoShape.BeginShape(OIV.Inventor.Actions.SoAction, OIV.Inventor.Nodes.SoShape.TriangleShapes, OIV.Inventor.Details.SoFaceDetail).

(Inherited from SoShape.)
Public methodEquals
Determines whether the specified Object is equal to the current Object.
(Inherited from Object.)
Public methodFieldsAreEqual

Returns true if this object's fields are exactly equal to fc's fields.

(Inherited from SoFieldContainer.)
Public methodGet

Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.

(Inherited from SoFieldContainer.)
Public methodGetAllFields

Returns a list of fields, including the eventIn's and eventOut's.

(Inherited from SoFieldContainer.)
Public methodGetAlternateRep

This method is called by actions to allow the node to provide an "alternate representation" when appropriate (typically depending on the action type).

(Inherited from SoNode.)
Public methodGetBoundingBox

Implements bounding box method using virtual OIV.VolumeViz.Nodes.SoFenceSlice.ComputeBBox(OIV.Inventor.Actions.SoAction, OIV.Inventor.SbBox3f@, OIV.Inventor.SbVec3f@) method.

(Overrides SoVolumeShapeGetBoundingBox(SoGetBoundingBoxAction).)
Public methodGetEventIn

Returns a the eventIn with the given name.

(Inherited from SoFieldContainer.)
Public methodGetEventOut

Returns the eventOut with the given name.

(Inherited from SoFieldContainer.)
Public methodGetField

Returns a the field of this object whose name is fieldName.

(Inherited from SoFieldContainer.)
Public methodGetFieldName

Returns the name of the given field in the fieldName argument.

(Inherited from SoFieldContainer.)
Public methodGetFields

Appends references to all of this object's fields to resultList, and returns the number of fields appended.

(Inherited from SoFieldContainer.)
Public methodGetHashCode
Overrides GetHashCode().
(Inherited from SoNetBase.)
Public methodGetMatrix
(Inherited from SoNode.)
Public methodGetName

Returns the name of an instance.

(Inherited from SoBase.)
Public methodGetPrimitiveCount

Counts number of primitives produced by this shape.

(Inherited from SoShape.)
Public methodGetRenderEngineMode

Returns the supported Render engine mode.

(Inherited from SoNode.)
Public methodGetRenderUnitID
(Inherited from SoVolumeShape.)
Public methodGetShapeType

Gets the current shape Full Scene Antialiasing type.

(Inherited from SoShape.)
Public methodGetStringName (Inherited from SoBase.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Public methodGLRender
Public methodGLRenderBelowPath
(Inherited from SoNode.)
Public methodGLRenderInPath
(Inherited from SoNode.)
Public methodGLRenderOffPath
(Inherited from SoNode.)
Public methodGrabEventsCleanup
(Inherited from SoNode.)
Public methodGrabEventsSetup
(Inherited from SoNode.)
Public methodHandleEvent
(Inherited from SoNode.)
Public methodHasDefaultValues

Returns true if all of the object's fields have their default values.

(Inherited from SoFieldContainer.)
Public methodIntersectGeometry

Return true if the given tile has geometry.

Public methodIsBoundingBoxIgnoring

Used by BoundingBoxAction to know if bounding box computation should be ignored or not.

(Inherited from SoShape.)
Public methodIsNotifyEnabled

Notification is the process of telling interested objects that this object has changed.

(Inherited from SoFieldContainer.)
Public methodIsOverride

Returns the state of the override flag.

(Inherited from SoNode.)
Public methodStatic memberIsSupported
Calls IsSupported((OIV.Inventor.Misc.SoState ^)nullptr).
Public methodStatic memberIsSupported(SoState)

Returns true if graphic card can render an OIV.VolumeViz.Nodes.SoFenceSlice.

Public methodIsSynchronizable

Gets the ScaleViz synchronizable state of this object.

(Inherited from SoBase.)
Public methodPick
(Inherited from SoNode.)
Public methodRayPick

Implements picking along a ray by intersecting the ray with each primitive generated by subclass.

(Overrides SoShapeRayPick(SoRayPickAction).)
Public methodSearch
(Inherited from SoNode.)
Public methodSet

Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.

(Inherited from SoFieldContainer.)
Public methodSetName (Inherited from SoBase.)
Public methodSetOverride

Turns the override flag on or off.

(Inherited from SoNode.)
Public methodSetRenderProgress

Set an application defined OIV.Inventor.SoProgressIndicator object which will raise an event before and after the rendering task, before and after each subtask (in this case: Texture creation and Geometry creation) and after each step in the subtasks which represents in most cases individual tiles of data.

(Inherited from SoVolumeShape.)
Public methodSetShapeType

set the antialiasing type for this shape.

(Inherited from SoShape.)
Public methodSetSynchronizable

Sets this to be a ScaleViz synchronizable object.

(Inherited from SoBase.)
Public methodSetToDefaults

Sets all fields in this object to their default values.

(Inherited from SoFieldContainer.)
Public methodShapeVertex

add a primitive vertex to the shape prevously started with OIV.Inventor.Nodes.SoShape.BeginShape(OIV.Inventor.Actions.SoAction, OIV.Inventor.Nodes.SoShape.TriangleShapes, OIV.Inventor.Details.SoFaceDetail).

(Inherited from SoShape.)
Public methodToString
Converts this SoBase structure to a human readable string.
(Inherited from SoBase.)
Public methodTouch

Marks an instance as modified, simulating a change to it.

(Inherited from SoNode.)
Public methodWrite
(Inherited from SoNode.)
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Properties
  NameDescription
Public propertyalphaUse

Specifies how to use the alpha component of each voxel's RGBA value.

(Inherited from SoSlice.)
Public propertyalternateRep

This field optionally holds a subgraph containing only core Open Inventor nodes that can be used for rendering when VolumeViz is not available.

(Inherited from SoSlice.)
Public propertyaxis

Extrusion axis: X, Y, or Z.

Public propertyboundingBoxIgnoring

Whether to ignore this node during bounding box traversal.

(Inherited from SoShape.)
Public propertybumpScale

Specifies the intensity of the bump mapping effect.

(Inherited from SoSlice.)
Public propertycomposition Obsolete.

Specifies color composition mode.

(Inherited from SoVolumeShape.)
Public propertydataSetId

Specifies the OIV.VolumeViz.Nodes.SoVolumeData node to use.

Public propertyenableBumpMapping

Specifies if a bump mapping effect will be applied to the slice.

(Inherited from SoSlice.)
Public propertyinterpolation

Interpolation mode.

(Inherited from SoVolumeShape.)
Public propertyIsDisposable
ISafeDisposable interface implementation.
(Inherited from SoDisposable.)
Public propertylargeSliceSupport

Activate/deactivate direct loading of full resolution slice data.

(Inherited from SoSlice.)
Public propertypoints

Set of points defining a lineset.

Public propertyUserData
Gets or sets the user data to be contained by the field container.
(Inherited from SoFieldContainer.)
Public propertyuseRGBA

Specifies whether to create RGBA textures.

(Inherited from SoSlice.)
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Remarks

This node renders a strip (connected series) of slices. The strip is defined by a set of 2D vertices that form a polyline. Each segment of the polyline is extruded along the axis specified in the OIV.VolumeViz.Nodes.SoFenceSlice.axis field to form (in effect) an oblique slice. The default axis is Z, so the 2D points are treated as (X,Y) values. The points may be outside the 3D extent of the volume, but only the portion of the slice inside the volume will be drawn (subject to region of interest and other clipping nodes).

The OIV.VolumeViz.Nodes.SoVolumeData node on which this shape is applied can be specified with OIV.VolumeViz.Nodes.SoFenceSlice.dataSetId. When this field is set to 0, the last OIV.VolumeViz.Nodes.SoVolumeData node on state is used.

A similar effect could be obtained using volume geometry (e.g. OIV.VolumeViz.Nodes.SoVolumeFaceSet), but OIV.VolumeViz.Nodes.SoFenceSlice is more convenient and is optimized for this specific case.

The 2D coordinates are interpreted according to the following table. See the code example below.

Fence axis Coordinate axes
X Y , Z
Y Z , X
Z X , Y

For a non-RGBA (scalar valued) volume, each voxel's RGBA value is determined by the current OIV.LDM.Nodes.SoDataRange and OIV.LDM.Nodes.SoTransferFunction. The current diffuse color and transparency (set, for example, with an OIV.Inventor.Nodes.SoMaterial node) modify the appearance of the slice. This means that, for example, the current transparency can be used as a global alpha value to modulate the overall opacity of the slice. For an RGBA volume each voxel's RGBA value comes directly from the volume data.

The interpolation field controls how the texture is interpolated.

The alphaUse field (OIV.VolumeViz.Nodes.SoSlice) controls how the voxel's alpha component is used when drawing the fence slice.

Optionally a bump mapping effect may be applied. Normal vectors are automatically computed from the data value gradient. The enableBumpMapping and bumpScale fields (OIV.VolumeViz.Nodes.SoSlice) control whether bump mapping is active and the intensity of the effect.

Notes:

  • Transformation matrices: The volume size and orientation (like geometry) can be modified by transformation nodes in the scene graph and this in turn modifies the appearance of volume visualization nodes. However the same transformation must be applied to the volume data node and all volume visualization nodes associated with that volume. So effectively any transformation nodes that affect the volume must be placed before the volume data node.

  • Picking: The entire slice is pickable, even where it is transparent as a result of the current transfer function. Currently OIV.VolumeViz.Nodes.SoFenceSlice does not provide an OIV.Inventor.Details.SoDetail object.

  • Interpolation: Interpolation is specified using the interpolation field. The default (LINEAR) does bi-linear interpolation between voxel values. The NEAREST value can be used to display individual voxels. For best image quality we recommend using the MULTISAMPLE_12 value.

  • Data range: By default VolumeViz maps the entire range of the voxel's data type (e.g. 0..65535 for unsigned short) into the colormap. This is often correct for byte (8 bit) voxels, but seldom correct for 16 bit voxels and never correct for floating point voxels. Use an OIV.LDM.Nodes.SoDataRange node to specify the actual (or desired) range of data values to be mapped. Also use an OIV.LDM.Nodes.SoDataRange node to implement brightness/contrast control like the Window/Level setting commonly used with medical images.

  • Clipping: Volume primitives can be clipped using a region of interest (OIV.LDM.Nodes.SoROI), geometry (OIV.VolumeViz.Nodes.SoVolumeClippingGroup) and/or height fields (OIV.VolumeViz.Nodes.SoUniformGridClipping). They are also clipped by OpenGL clipping planes (OIV.Inventor.Nodes.SoClipPlane), but we recommend using the VolumeViz clipping nodes instead.

  • Material: The color of each voxel is modulated by the current diffuse color in the traversal state. The default diffuse color is 0.8,0.8,0.8. This results in full intensity values in the color map being displayed as 80% intensity. Therefore we recommend adding an OIV.Inventor.Nodes.SoMaterial node before the slice and setting its diffuseColor field to full white (1,1,1).

  • Transparency:

    • Typically the color map (OIV.LDM.Nodes.SoTransferFunction) used for volume rendering (OIV.VolumeViz.Nodes.SoVolumeRender) assigns transparency (alpha < 1) to some voxel values. If you want to use the same color map for slice rendering, but render the slice completely opaque, set the alphaUse field to ALPHA_OPAQUE. This overrides the alpha values in the color map (or an RGBA volume). However it does not affect transparency assigned using an OIV.Inventor.Nodes.SoMaterial node.

    • If you want to adjust the overall transparency of the slice, add an OIV.Inventor.Nodes.SoMaterial node and set its transparency field (keeping alphaUse set to ALPHA_AS_IS). Effectively a scale factor 1-transparency is applied to each voxel's alpha value.

    • Intersecting transparent slices cannot be rendered correctly by the basic blending transparency algorithms. To render this case correctly, set the transparency algorithm to SORTED_PIXEL using the viewer class or OIV.Inventor.Actions.SoGLRenderAction.

  • Voxel edges: The edges of the voxels can also be rendered. See options in the OIV.VolumeViz.Nodes.SoVolumeRenderingQuality node.

  • Custom shaders: The current OIV.VolumeViz.Nodes.SoVolumeShader node, if any, allows custom shaders to be defined for special computation or rendering effects, including blending multiple volumes.

  • Composition with Multiple Data: It is possible to compose datasets that have different dimensions, tile sizes and transformations. In order to help fetch the correct data values in custom shaders, texture coordinates conversion functions are provided in the VolumeViz/vvizStructure.h shader include. For instance,

    vec3 VVizTextureToTextureVec(in VVizDataSetId datasetSrc, in VVizDataSetId datasetDst, in vec3 texCoord);
    can be used to convert texture coordinates related to one dataset to texture coordinates related to another dataset. The conversion is based solely on the transformations applied to each dataset, which are defined by their model matrix and their extent. Please note that the model matrix of a dataset is defined by to the OIV.Inventor.Nodes.SoTransformation nodes that are placed before the OIV.LDM.Nodes.SoDataSet node in the order of the traversal.

  • Performance:

    • Tile size: For backward compatibility, the default tile size is still only 64. This is quite small for modern CPU/GPU hardware. The smaller the tile size, the larger the total number of tiles that must be managed by VolumeViz. This overhead can be significant, especially for operations that require reloading the data textures on the GPU, for example, changing the data range (OIV.LDM.Nodes.SoDataRange). For smaller volumes, like 512^3, it can be efficient to set the tile size large enough to contain the entire volume. For very large volumes, larger tile sizes are efficient for OIV.VolumeViz.Nodes.SoVolumeRender but somewhat inefficient for slice rendering because complete tiles must be loaded even though the slice only uses part of the data. Applications should experiment. For volumes stored in LDM file format, the tile size must be specified when the volume is converted to LDM (see OIV.LDM.Converters.SoConverter and the "-t" option). For other data data formats the tile size can be specified using the OIV.VolumeViz.Nodes.SoVolumeData node's ldmResourceParameters field, but only after setting the filename field or calling the SetReader()method.

    • Tile cache policy: It specifies how the tiles are stored in CPU memory. The selected policy can significantly impact the data loading performance versus the CPU memory footprint. See OIV.LDM.Nodes.SoLDMResourceParameters.tileCachePolicy for detail.

  • Hardware requirements: This node needs a graphic card with support for GLSL shader, vertex buffer objects (VBO) and framebuffer object (FBO). Use the OIV.VolumeViz.Nodes.SoFenceSlice.IsSupported(OIV.Inventor.Misc.SoState) method to check if the current graphics board can render a FenceSlice.

EXAMPLE

Please see OIV.VolumeViz.Nodes.SoObliqueSlice for a complete code example. The following shows how to set up the OIV.VolumeViz.Nodes.SoFenceSlice.axis and OIV.VolumeViz.Nodes.SoFenceSlice.points fields of OIV.VolumeViz.Nodes.SoFenceSlice.

SoFenceSlice fenceSlice   = new SoFenceSlice();
 fenceSlice.axis.Value = SoFenceSlice.AxisType.Y;
 fenceSlice.points[0] = new SbVec2f(-0.2f, -0.66f);
 fenceSlice.points[1] = new SbVec2f(0.2f, -0.4f);
 fenceSlice.points[2] = new SbVec2f(-0.2f, 0.4f);
 fenceSlice.points[3] = new SbVec2f(0.2f, 0.66f);

Fence slice on Y axis (Colt example data set):
Fence slice on X axis (Colt example data set):
Fence slice on Z axis (Colt example data set):

FILE FORMAT/DEFAULT

FenceSlice {
dataSetId 0
points [ ]
axis Z
interpolation LINEAR
alphaUse ALPHA_BINARY
useRGBA false
alternateRep NULL
enableBumpMapping false
bumpScale 1.0
}

ACTION BEHAVIOR

OIV.Inventor.Actions.SoGLRenderAction Draws a textured shape based on current OIV.VolumeViz.Nodes.SoVolumeData, OIV.LDM.Nodes.SoTransferFunction, and OIV.LDM.Nodes.SoROI nodes.

OIV.Inventor.Actions.SoGetBoundingBoxAction Computes the bounding box that encloses the fence slice.

See Also