public class SoObliqueSlice extends SoSlice
SoVolumeData node and the plane defined by the plane field.
For a non-RGBA (scalar valued) volume, each voxel's RGBA value is determined by the current SoDataRange and SoTransferFunction. The current diffuse color and transparency (set, for example, with an 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 (SoSlice) controls how the voxel's alpha component is used when drawing the slice.
Optionally a bump mapping effect may be applied. Normal vectors are automatically computed from the data value gradient. The enableBumpMapping and bumpScale fields (SoSlice) control whether bump mapping is active and the intensity of the effect.
Notes:
SoObliqueSliceDetail class allows you to get the voxel position and value after picking.
SoTranslate1Dragger. However the dragger's field values must be converted to an SbPlane. For a dragger that has a convenient "plane" field that can be directly connected, see the ClipPlaneDragger article in the Resources section of the Open Inventor Forum: 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 TRILINEAR or MULTISAMPLE_12 value.
SoDataRange node to specify the actual (or desired) range of data values to be mapped. Also use an SoDataRange node to implement brightness/contrast control like the Window/Level setting commonly used with medical images.
SoROI), geometry (SoVolumeClippingGroup) and/or height fields (SoUniformGridClipping). They are also clipped by OpenGL clipping planes (SoClipPlane), but we recommend using the VolumeViz clipping nodes instead.
SoMaterial node before the slice and setting its diffuseColor field to full white (1,1,1).
SoTransferFunction) used for volume rendering (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 SoMaterial node. 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. SoGLRenderAction.
SoVolumeRenderingQuality node.
SoVolumeShader node, if any, allows custom shaders to be defined for special computation or rendering effects, including blending multiple volumes.
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 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. SoConverter and the "-t" option). For other data data formats the tile size can be specified using the SoVolumeData node's
ldmResourceParameters field, but only after setting the
filename field or calling the setReader() method. SoDataRange). We recommend setting this variable to false (see SoPreferences) unless saving CPU memory is critical.
For simple data sets, a basic VolumeViz rendering could be achieved with only a few nodes: minimally an SoVolumeData node to identify the data set and one rendering node. However most data sets need at least some of the additional nodes shown here in order to get a correct and useful rendering. Most applications will need additional nodes to take advantage of region of interest, interaction, clipping and other VolumeViz features. Please consider the code shown here as simply a guideline and a starting point for exploring the many powerful features available in Open Inventor.
Note that some of the property nodes (data, material, color map, etc) will typically be shared by multiple rendering nodes. In other words the volume usually only needs to be loaded once, using a single SoVolumeData node, then multiple slices and/or regions can be rendered using that data node.
Also note that this example is for a data volume, where each voxel can be considered a discrete sample from a continuous data field and interpolation should be used to compute values between voxel centers. If you are rendering a label volume, then each voxel is an "id" assigning that voxel to a specific material, object, etc. In this case, set the interpolation field to NEAREST to disable interpolation.
// Default setting can be a performance bottleneck SoPreferences.setValue( "LDM_USE_IN_MEM_COMPRESSION", "0" ); // Keep volume viz separate from geometry SoSeparator volSep = new SoSeparator(); root.addChild( volSep ); // Load volume data SoVolumeData volData = new SoVolumeData(); volData.fileName.setValue( "$OIVJHOME/data/VolumeViz/3DHead.vol" ); volSep.addChild( volData ); // Set range of data values to visualize. // Not required for 8-bit voxels, critical for larger data types. // The getMinMax() call may be expensive for non-LDM file formats. SoDataRange volRange = new SoDataRange(); if (volData.getDatumSize() > 1) { double[] minmax; minmax = volData.getDoubleMinMax(); volRange.min.setValue( minmax[0] ); volRange.max.setValue( minmax[1] ); } volSep.addChild( volRange ); // Load opaque intensity ramp SoTransferFunction volTF = new SoTransferFunction(); volTF.predefColorMap.setValue( SoTransferFunction.PredefColorMaps.INTENSITY ); volSep.addChild( volTF ); // Display slice at full intensity SoMaterial volMat = new SoMaterial(); volMat.diffuseColor.setValue( 1, 1, 1 ); volSep.addChild( volMat ); // Remove tile boundary artifacts while moving. SoVolumeShader volShader = new SoVolumeShader(); volShader.interpolateOnMove.setValue( true ); volSep.addChild( volShader ); // Display a Z axis slice at center of volume SoObliqueSlice slice = new SoObliqueSlice(); SbBox3f volext = volData.extent.getValue(); SbVec3f center = volext.getCenter(); slice.plane.setValue( new SbPlane( new SbVec3f(0,0,1), center.getZ() ) ); slice.interpolation.setValue( SoVolumeShape.Interpolations.MULTISAMPLE_12 ); volSep.addChild( slice );
File format/default:
ObliqueSlice {
| plane | 0, 0, 1, 0 |
| interpolation | LINEAR |
| alphaUse | ALPHA_BINARY |
| useRGBA | false |
| alternateRep | NULL |
| enableBumpMapping | false |
| bumpScale | 1.0 |
Action behavior:
SoGLRenderAction
Draws a textured polygon based on current SoVolumeData, SoTransferFunction, and SoROI nodes.
SoGetBoundingBoxAction
Computes the bounding box that encloses the slice.
See also:
SoVolumeData, SoDataRange, SoTransferFunction, SoROI, SoSlice, SoOrthoSlice, SoVolumeShader
SoSlice.AlphaUsesSoVolumeShape.Compositions, SoVolumeShape.InterpolationsSoShape.ShapeTypesInventor.ConstructorCommand| Modifier and Type | Field and Description |
|---|---|
SoSFPlane |
plane
Plane defining the slice.
|
ALPHA_AS_IS, ALPHA_BINARY, ALPHA_OPAQUE, alphaUse, alternateRep, bumpScale, enableBumpMapping, largeSliceSupport, useRGBAALPHA_BLENDING, composition, COMPOSITION_LAST, CUBIC, interpolation, LINEAR, MAX_INTENSITY, MIN_INTENSITY, MULTISAMPLE_12, NEAREST, SUM_INTENSITY, TRILINEARboundingBoxIgnoring, LINES, POINTS, POLYGONS, TEXTVERBOSE_LEVEL, ZeroHandle| Constructor and Description |
|---|
SoObliqueSlice()
Constructor.
|
intersectgetShapeType, isPrimitiveRestartAvailable, isPrimitiveRestartAvailableaffectsState, callback, copy, copy, distribute, doAction, getAlternateRep, getBoundingBox, getByName, getMatrix, getPrimitiveCount, getRenderUnitID, GLRender, GLRenderBelowPath, GLRenderInPath, GLRenderOffPath, grabEventsCleanup, grabEventsSetup, handleEvent, isBoundingBoxIgnoring, isOverride, pick, rayPick, search, setOverride, touch, writecopyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaultsdispose, getEXTERNPROTO, getName, getPROTO, isDisposable, isSynchronizable, setName, setSynchronizablegetAddress, getNativeResourceHandle, startInternalThreads, stopInternalThreadspublic final SoSFPlane plane
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