public bool ReadLightRange { get; set; }

Property Value

ReadLightRange gets or sets a Boolean that specifies if Range for PointLight and SpotLight is read. Default value is false.

WPF 3D is using per vertex lighting. This means that lighting is calculated for each vertex and than interpolated to the pixels between vertexes. If WPF 3D would use per pixel lighting, than lighting would be calculated for each pixel. Per vertex lighting is much faster and can run on older hardware but when using PointLight and SportLight is has very big drawbacks.

For example if we have a scene with one plane that is created from 2 triangles and one PointLight that has Position and Range set so that only the center of the plane would be visible, the plane would be rendered completely black - as if no light would illuminate the plane.

Because of that problems the default value for ReadLightRanges is set to false - in this case the Range for PointLights and SpotLights is set to Infinity - it is better to show more than nothing.

Reference