Manipulating Light Sources

This task shows you how to manipulate light sources along predefined circles that are centered on the light target.

1. Click the Light Manager icon .

   The 'Light Manager' dialog box is displayed.

2. In the dialog box 'Light Manager' click the direction light source Light.1 in the Lights table and rename it to 'Direction'.

3. Click onto the light source manipulator to activate the Manipulation Mode.

4. Click onto the arcs at the manipulator to display the direction circles.

5. Drag the cursor along a circle to modify the light direction.

6. In the dialog box 'Light Manager', click onto the icon 'Create Light Source' in the frame 'Light Source Options'. A new light source type Direction is created.

7. Click onto the icon 'Active Light Source Type - Spot' in the frame 'Type'. The light source will be changed to a light source type Spot.

8. Change the light source name to 'Spot'.

9. Activate the Manipulation Mode by clicking onto the manipulator.

10. Click onto the line representing the Y axis to move the manipulator along this axis.

11. Click onto the handle at the end of the manipulator to rotate the light source.

12. Click onto the handle at the end of the manipulator to move the target point.

• Lights: The lights table field displays the light sources defined in the current CATPart.
  When creating or deleting light sources, the table is automatically updated.
  Each light source created is given a default name with a consecutive number. It can be renamed after clicking twice onto the name. Each light source created lists the following information:
  • Name: Name of light source created.
  • On/Off: Indicates if the light source is switched on or of within the CATPart.
  • Type: Indicates the type of light source.
  • Attached: Indicates if the light source is attached to the view or model.

  Interactions: The selected light source will become the current light source, i. e., its current parameter settings are displayed in the menu and can be modified. When manipulating the light source, the parameters in the dialog box are updated dynamically. For the selected light source, the settings in the tabs Position, Parameter, and Spot Parameter can be modified.

• Type: With the following icons the type of the current light source can be selected:
  • Spot: The light of a spot light source is similar to a flashlight. It is useful for tuning the lighting of each object individually.
    Spot light sources are defined by a direction vector, a light cone, the dehidral angle of which can be modified dynamically. The transition to the environment can be hard or soft (see options Angle and Sharpness in the Spot Parameters tab).
     

    	For the Spot light source the following manipulation possibilities are available:
    	Rotate:	Rotate the manipulator using the handle at the rear end.
    	Move:	Move the manipulator along the selected axis.
    	Change target point:	Move the handle at the end of the light beam line.

  • Point: Point light sources radiate light symmetrically into all directions (like a plain light bulb.
    The point light source can only be moved freely.
    
  • Direction: Beam light sources produce parallel light from a constant direction (like sunlight).
    The direction light source can only be rotated.
    

• New: A new light source depending on the Type selected is created with the current settings.
  The number of definable light sources is limited to 8.
• Delete: The light source selected in the lights table is deleted.
• On/Off: Switching on and off the current light source.
• Attached:
  • View: The light source is fixed to the view, i. e. in case of geometry rotations its position remains unchanged.
  • Model: The light source is fixed to the model coordinate system, i. e. it will be rotated together with the geometry.
• Global: The display of the light source symbols is globally switched on or off.

• Position: Only available for the light source types Point and Spot.
  Defines the exact X, Y, and Z model coordinate values of the selected light source.
  With the check button Position can be defined a point element as light source position.
• Direction: Only available for the light source types Direction and Spot.
  Defines the exact X, Y, and Z direction coordinates of the selected light source.
  In the direction field can be defined the direction via the contextual menu.
  With the direction buttons X, Y, and Z, the light sources are aligned to the corresponding axis. With can be inverted the direction of the selected axis.

• White: The light color is white.
• Color: Defines the color of the light source. With  can be activated the dialog box Color in which the light color can be selected.
• Intensity: Defines the light intensity using the slider or by entering a value directly in the text field.
  The intensity of a light source is the maximal lightness value of three colors (ambient, diffuse and specular).

• Ambient: Defines the intensity of light emitted in any direction by the object, even if not lit by any light source.

• Diffuse: Defines the intensity of light diffused by the object when lit by a light source.

• Specular: Defines the intensity and color of light reflected in one particular direction. This coefficient affects the highlight on shiny surfaces.

• Angle: Setting of the angle of the spot light cone. In case of setting the Angle to 90° and the Sharpness to 0 a point light source with the same position will result.
• Sharpness: Setting of the sharpness of the spot light cone. Higher values concentrate the light beam in the centre of the light cone.

Context Menus