Realsoft 3D supports a rich set of light sources. The light source attributes described below include quite extensive controls. Even more lighting power can be achieved by using materials that define custom lighting effects using a Light properties shader.
The controls that are available for most light source types are listed below.
Intensity: Controls the brightness of the light source. The intensity value of a light source is combined with its RGB color value. For example:
intensity=0.5, color=(0.8, 0.7, 0.6)->light color=(0.4, 0.35, 0.3).
Diffuse Only: If set, the light source creates only the default diffuse shading i.e. the illumination is proportional to the angle at which light hits the surface. Specular lighting and other VSL defined shading effects will be ignored.
None - Illumination does not depend on the distance.
Local - Illumination fades to zero within the falloff radius.
Distance - Illumination is inversely proportional to the distance. Light intensity decreases to 50% when the distance is doubled.
Distance squared - A physically correct falloff for point light sources. Intensity decreases rapidly by distance.
Radius: The falloff distance. Local falloff drops to zero at this distance, 'Distance' and 'Distance squared' falloffs decrease to 50 % at this distance.
Shadow casting properties are available for all light source types. Point and spot lights support shadows mapping.
No shadows: The light source does not cast any shadows. This kind of light source renders quickly.
Ray traced shadows: Shadows of the light source are computed using ray tracing. Such shadows are realistic and obey material properties (glass object do not cast black shadows etc.).
Mapped shadows: Shadows are first rendered to a bitmap which is then filtered in a suitable way. This kind of shadows have smooth edges and often render quickly. However, mapped shadows are more inaccurate than ray traced shadows and do not support shadow translucency.
Resolution: The accuracy of the shadow map. Both x and y dimensions use the same pixel resolution. A low resolution, for example 200 pixels, will make shadow computations quick but inaccurate. A higher resolution, for example 1000 pixels, is accurate, but shadow map rendering takes much longer time.
Static: If set, shadow maps are not deleted after rendering. Consequent rendering steps can then use the existing shadow maps. This speeds up rendering. The result is correct if the scene does not change near the light source in question (e.g. when only the camera is animated).