public class SoVolumeClippingGroup extends SoGroup
SoVolumeClippingGroupnode. Polygon clipping can remove the voxels outside the shape or the voxels inside the shape. Polygon clipping can be used in seismic applications to clip outside a fault block or geobody, in medical applications to cut away an arbitrary region, in core sample applications to apply cylindrical clipping and many other uses.
When this node is in the scene graph before a VolumeViz rendering node, all shapes under the
SoVolumeClippingGroup will be used to clip the volume. These shapes will not be displayed.
The geometry defined under
SoVolumeClippingGroup must represent a set of closed surfaces otherwise the result is unpredictable.
The clipping group may include transform nodes, e.g.
SoTransform, to scale, rotate and translate the geometry. The transformed geometry will be used for clipping.
In general, do not put draggers or manipulators, e.g.
SoTabBoxDragger, in the clipping group. The geometry of the dragger will also be used for clipping and the results may be unexpected. One exception is if the dragger is configured to use the clipping shape as "proxy" geometry (see
SoInteractionKit.setPartAsPath()). A better solution is to put the dragger in the scene graph outside the clipping group, add a transform node to the clipping group and connect the fields of the dragger to the fields of the transform node (see
The clipping result is based on the odd-winding rule, so the result is not simply the union or the intersection of the closed surfaces. If the goal is to define a clipping shape which is the result of the intersection/union of multiple closed surfaces, consider using the
SoCSGShape node as a child of
In some cases the number of passes specified may not be enough to clip correctly with the specified geometry. The
numPasses field allows you to increase the clipping quality, for example when using shapes with a lot of concavity. To query the maximum allowed number of passes, which depends on your graphics card, use the static method
getMaxNumPasses(). The setNotEnoughPassCallback() method allows the application to be notified when numPasses is not sufficient.
Standard clipplanes (see
SoClipPlane) affect VolumeViz rendering nodes, but the VolumeViz specific clipping nodes generally provide better performance and allow much more complex clipping. Simple axis-aligned clipping can be done more efficiently using the
SoROI node. The
SoUniformGridProjectionClipping nodes clip against height-field surfaces (e.g. seismic horizons). The
SoVolumeMask node clips against a boolean mask volume on a per-voxel basis.
When using a custom
SoVolumeShader with this node and redefining the
main() function, you must call
VVizClipVoxel() in the
main() function if you are writing a fragment shader. If you don't do this you will get a GLSL compilation error or clipping won't work.
Because this node uses special textures, all texture units between IVVR_FIRST_RESERVED_TEXTURE_UNIT (or
SoFragmentShader.getMaxTextureImageUnit()-SoShaderProgram.getNumReservedTextures() if this variable is not set) and :
SoVolumeClippingGroup requires the following OpenGL extensions. Use the
isSupported() static method to check for support on the current graphics board or use the IvReport tool to print a report about the graphics board.
Because this node requires closed geometry, clipping planes (
SoClipPlane) are automatically disabled when computing the clipping shape.
When used inside an
SoOffscreenVolumeRender results might be incorrect. In specific cases geometry might be seen as opened.
The following code clips a volume with a cone:
SoVolumeClippingGroup volClipGroup = new SoVolumeClippingGroup(); volClipGroup.addChild( new SoCone() ); SoSeparator volSep = new SoSeparator(); volSep.addChild( volumeData ); volSep.addChild( transferFunction ); volSep.addChild( volClipGroup ); volSep.addChild( volumeRender ); root.addChild( volSep );
|Clipping object||Clipping applied to a volume|
|Modifier and Type||Field and Description|
If true, voxels inside the clipping object will be drawn, voxels outside will be clipped.
Number of passes used to do the clipping.
|Constructor and Description|
|Modifier and Type||Method and Description|
Returns the maximum number of passes supported by the hardware.
Indicates if volume clipping is supported by your graphics board.
addChild, findChild, getChild, getNumChildren, insertChild, removeAllChildren, removeChild, removeChild, replaceChild, replaceChild
affectsState, 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, write
copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults
dispose, getEXTERNPROTO, getName, getPROTO, isDisposable, isSynchronizable, setName, setSynchronizable
getAddress, getNativeResourceHandle, startInternalThreads, stopInternalThreads
public final SoSFInt32 numPasses
public final SoSFBool clipOutside
public static int getMaxNumPasses()
public static boolean isSupported()
public static int getMaxNumPasses(SoState state)
public static boolean isSupported(SoState state)