Visualization implementing complex mechanisms for data representation.


Visualization module provides ready-to-use algorithms to create graphic presentations from various objects: shapes, meshes, etc.

In Open CASCADE Technology visualization is based on the separation of CAD data and its graphical presentation. The presentations can be customized to take the specificity of your application into account.

The module also supports a fast and powerful interactive selection mechanism.

The view facilities provided by OCCT range from low-level tools working with basic geometry and topology (such as NURBS visualization with control points and nodes, rendering of isolines to estimate speed and quality of parameterization, or rendering of a parametric profile of edges) to high-level tools for real time quality rendering of models using ray tracing: shades, reflections, transparency, anti-aliasing, etc.

Here are just a few examples:

  • Camera-driven view projection and orientation. It is possible to choose between perspective, orthographic and stereographic projection.
  • Real-time ray tracing technique using recursive Whitted's algorithm and Bounded Volume Hierarchy effective optimization structure.

Real time visualization by ray tracing method

  • Support of GLSL shaders. The shader management is fully automatic, like with any other OpenGL resource.

Fragment shader implementing custom clipping surface

  • Support of standard and custom materials, defined by transparency, diffuse, ambient and specular reflection and refraction index. The latter allows implementing transparent materials, such as glass, diamond and water.

Simulation of a glass cover

  • Optimization of rendering performance through the algorithms of:
    • View frustum culling, which skips the presentation outside camera at the rendering stage and
    • Back face culling, which reduces the rendered number of triangles and eliminates artifacts at shape boundaries.
  • Definition of clipping planes through the plane equation coefficients. Ability to define visual attributes for cross-section at the level or individual clipping planes. In the image below different parts of the rocket are clipped with different planes and hatched.
  • Possibility to flexibly adjust appearance of dimensions in a 3D view. The 3D text object represents a given text string as a true 3D object in the model space.

Display of shape cross-section and dimensions

For more details see Visualization User's Guide.

The visualization of OCCT topological shapes by means of VTK library provided by VIS component is described in a separate VTK Integration Services User's Guide.

See also: E-learning & Training.