IDLgrVolume

A volume object represents a mapping from a three-dimensional array of data to a three-dimensional array of voxel colors, which, when drawn, are projected to two dimensions.

An IDLgrVolume object is an atomic graphic object; it is one of the basic drawable elements of the IDL Object Graphics system, and it is not a container for other objects.

Creating a Volume Object

A volume object contains a three dimensional data array of voxel values and a set of rendering attributes. The voxel array is mapped to colors and opacity values through a set of lookup tables in the volume object. Several rendering methods are provided to draw the volume to a destination.

To create a volume object, create a three dimensional array of voxels and pass them to the IDLgrVolume::Init method. Voxel arrays must be of BYTE type. For example, the following code will create a simple volume data set and create a volume object which uses it:

data = BYTARR(64,64,64, /NOZERO)

FOR i=0,63 DO data[*,i,0:i] = i*2

data[5:15, 5:15, 5:55] = 128

data[45:55, 45:55, 5:15] = 255

myvolume = OBJ_NEW('IDLgrVolume', data)

XOBJVIEW, myvolume

The volume contains a shaded prism along with two brighter cubes (one located within the prism).

Superclasses

IDLitComponent

Creation

See IDLgrVolume::Init.

Properties

Objects of this class have the following properties. See IDLgrVolume Properties for details on individual properties.

ALL	ALPHA_CHANNEL
AMBIENT	BOUNDS
CLIP_PLANES	COMPOSITE_FUNCTION
DATA0	DATA1
DATA2	DATA3
DEPTH_CUE	HIDE
HINTS	INTERPOLATE
LIGHTING_MODEL	OPACITY_TABLE0
OPACITY_TABLE1	PARENT
REGISTER_PROPERTIES	RENDER_STEP
RGB_TABLE0	RGB_TABLE1
SHADER	TWO_SIDED
VALID_DATA	VOLUME_SELECT
XCOORD_CONV	XRANGE
YCOORD_CONV	YRANGE
ZBUFFER	ZCOORD_CONV
ZERO_OPACITY_SKIP	ZRANGE

In addition, objects of this class inherit the properties of all superclasses of this class.

Methods

This class has the following methods:

• IDLgrVolume::Cleanup
• IDLgrVolume::ComputeBounds
• IDLgrVolume::GetCTM
• IDLgrVolume::GetProperty
• IDLgrVolume::GetVertexAttributeData
• IDLgrVolume::Init
• IDLgrVolume::PickVoxel
• IDLgrVolume::SetProperty
• IDLgrVolume::SetVertexAttributeData

In addition, this class inherits the methods of its superclasses (if any).

Version History

5.0	Introduced
5.6	Added CLIP_PLANES keyword
6.0	Deprecated CUTTING_PLANES property
6.1	Added ALPHA_CHANNEL property
6.2	Removed NO_COPY property and documented as a keyword on IDLgrVolume::Init and IDLgrVolume::SetProperty
6.4	Added SHADER property