What is Modeling Transformation

Modeling transforms apply to objects; they scale, rotate, and move objects. Coordinate transforms scale, rotate, and move the viewport, where the viewport is the rectangle that encloses the region that is shown in the image. On the lower right, the objects remain untransformed, while the viewport is transformed.

A visualization system is not just a system to create an image of the data but can be used to manipulate the data to create different types of images. A model of a visualization system should link the system with the model of scientific investigation discussed above.Visualization can help form the link between hypothesis and experiment and between insight and revised hypothesis.

The developed model consists of a set of abstract modules. It is a controlled dual dataflow system. A generic basic module is shown below:

The Control is perfomed by the User. The internal data is the data the module works on and transforms.

Data Types

The different data types describe the dataflow between the different modules. The data types are as follows:

  • Control Data: data that activates and controls all the modules in the system.
  • User Input/Output: all forms of human - computer interaction. Input might be keyboard, mouse, light pen, etc. Output might be screen, hard copy device, sound (for sonification), etc. This is converted into the Metadata for the system modules.
  • Internal Data: the data that is allowed to flow through the system.
  • External Data: data that can be imported/exported to the system. This might be ascii data (from observation or simulation) or images.
  • Storable Data: data that can be stored and retrieved within the system.
  • Graphics Data: a reduced form of internal data that represents graphics primitives (2D or 3D)
  • Picture Data: a reduced form of graphics data (pixel map or 2D primitives for display or hardcopy)

Module Types

There are several different module types. Each different type can have multiple sub-types. A visualization system should allow for the user to customize existing modules and to construct new modules.

User Module: The user observes the system output and controls the system.

User Interface Module: this maps between the user’s world and the internals of the visualization system.

Base Graphics System takes geometry and other related information and transforms it into picture data for the User Interface module. Examples are graphics standards such as PHIGS, PEX, GL, OpenGL, etc.

A Visualization Technique module takes internal data derived from the external model (simulation or computation) and transforms it into a form suitable for the Base Graphics System module.
Data Manipulation modules perform transformations on the internal data. For examples of these data transformations.
Data Access modules allow data to be stored and/or retrieved, perhaps in a format specific to the visualization system.

A Data Import module imports data from an external source. Different Data Import modules will import different types of data.

A Data Export module exports data, as with the importing of data, different modules will export different types of data. A Command Interpreter translates command data into control data for other modules in the visualization system.

A Command Sequencer module allows for sequence of command data, e.g., for an animation.