Module: Cropped Volume ()

Description:

The seismic Cropped Volume module is a specialized Volume Rendering module provided for convenience in seismic visualizations. This module can be attached to a seismic volume data object in order to do texture-based direct volume rendering. The render style is set by default to volume skin and a seismic colormap is used (Amplitude_BlueBrownRed.am by default).

Connections:

Data [required]
The seismic volume data object to be visualized. See Seismic Volume Data Object.

ROI [optional]
Connection to a module providing a region-of-interest, like ROI Box Seismic. If such a module is connected, only the selected part of the volume will be displayed.

Colormap [optional]
Colormap used to visualize the data. By default, a seismic colormap is used. (Amplitude_BlueBrownRed.am)

Ports:

Render style

Volume rendering consists of drawing slices from back to front and compositing them according to the Composition port. Volume skin (the default value) is a cubic shape made of textured polygons whose textures are computed using the data. Both use a colormap for rendering.

Options

Lighting indicates if lighting is required. The default is false. Note that activating or deactivating lighting when using 2D/3D texture rendering will usually force the textures to be recreated, which may be slow.

Aligned slices indicates if slices must be drawn in a view-aligned manner. This value is used for 3D texturing only. Default is true.

Color table enables a transfer function lookup for monochrome data when RGBA lookup mode is on. When this option is activated, only a quarter of the texture memory is needed for RGBA rendering and the color table and its range can be modified in real-time (i.e., without pressing the Apply button). Note that due to incomplete OpenGL implementations, some graphics boards which claim to support color tables do not. If you see artifacts or only plain white cubes, disable this option. Default is false.

Options2

Move low resolution: if checked, a lower texturing resolution will be set in order to increase rendering performance when the user is interacting with the scene.

Composition

Specifies the color composition type. Alpha composes the slices by blending the R, G, B components for each pixel based on their alpha values. Sum adds slice colors along the viewing axis. (Not available on VolumePro hardware.) Max draws the maximum intensity for each pixel drawn along the viewing axis. Min draws the minimum intensity for each pixel drawn along the viewing axis.

Interpolation

Specifies the interpolation type (nearest value or linear interpolation).

Range

This port is only available if the module operates on a 3D scalar field and no colormap is connected. In this case, data values are mapped according to this range. Values smaller than the minimum are mapped to fully transparent (no absorption and no emission). Values larger than the maximum appear completely opaque and emit the maximum amount of light. Values in between are mapped proportionally.

Lookup

Only available if a colormap is connected. In Alpha mode, the colormap's alpha value is used for both absorption and emission. In LumAlpha mode, the colormap's alpha value is used for absorption, while the luminance is taken for (uncolored) emission. In RGBA mode, colored images are generated by using all four channels of the colormap.

Colormap

Port to select a colormap. By default, a seismic colormap is used (Amplitude_BlueBrownRed.am).

Gamma

Controls the shape of the transfer function when multi-channel fields are visualized. The opacity value is taken to be , (proportional to data values). The smaller the gamma value is, the more prominent regions with small data values will be.

Alpha scale

A global factor to change the overall transparency of the object independent of the data value.

Texture mode

2D texture mode requires some precomputation time but also works on machines which do not support hardware-accelerated 3D texturing. 3D mode requires less setup time and sometimes provides superior quality on high-end machines.

Number of slices

Only available in 3D texture mode. The larger this number, the better the image quality and the less the rendering performance.