The work area (user interface) > Viewports > Viewport lights > The light types
  
The light types
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The following refers only to viewport lighting, and not the light studios of the Creo Elements/Direct Rendering Module.
Creo Elements/Direct Modeling supports 16 different lights to simulate the illumination of a shaded part. Note that this will depend upon the capabilities of your particular graphics hardware.
Light number 0 is an ambient light, sometimes called diffuse light, which seems to come from all directions at once like the light on a cloudy day. For variations with light number 0, you are limited to the light color and its brightness. By default light number 0 is not active. The graphic shows its icon.
For the other 15 lights (or seven depending on the hardware configuration) which are all arranged around the part, you can select between three types as follows:
Directional light: parallel beams of light. All light hits the object from the same direction, like the light on a sunny day. For each parallel light you can modify color, brightness, and direction.
Positional light: light from a fixed source in all directions. The rays of light radiate out from the source like a light bulb without a lamp shade. The light may hit various areas of a single surface of the object at different angles. For each point light you can modify color, brightness, position, and attenuation distance.
Spot light: light from a fixed source that radiates along a defined cone. For each spot light you can modify color, brightness, direction, position, cone angle, attenuation distance, and spot power. For a spot light to have an effect, the light must fall on the vertex of a facet.
The number and type of the active lights influences the performance of your system.