vtkActor

vtkActor is a fundamental object in the Visualization Toolkit (VTK) used to represent visible objects within a VTK scene. It acts as a bridge between a geometric dataset and its visual representation. An actor is responsible for defining how a particular piece of geometry should be displayed, including its properties, position, and orientation.

An actor is typically composed of several key components. A vtkMapper is essential, as it converts the geometric data (e.g., points, lines, polygons) into rendering primitives that the graphics hardware can understand. The actor also holds a reference to a vtkProperty object, which defines visual attributes like color, opacity, specular intensity, and representation style (e.g., wireframe or surface). Furthermore, actors have a transformation matrix that controls their position, rotation, and scaling within the 3D scene.

To be rendered, a vtkActor must be added to a vtkRenderer. The renderer then orchestrates the drawing of all its actors, taking into account camera position and lighting conditions. Multiple actors can be added to a single renderer, allowing for the construction of complex scenes with various objects. The ability to manipulate individual actors independently makes vtkActor a powerful tool for interactive visualization.