The VRayIES is a V-Ray specific light source plugin that can be used to load and render real-world light distribution profile files (IES files). The VRayIES light is very similar to the 3ds Max Photometric lights, but is specifically optimized for the V-Ray renderer and typically renders faster.


[VRayLight parameters]enabled - turns the VRayIES light on and off.


enable viewport shading - when enabled the effect of the VRayIES light will be visible in the viewport


show distribution -


targeted - makes the VRayIES targeted.


IES file (button) - specify the .ies file that defines the light distribution.


rotation X/Y/Z - these options allow the user to rotate the light shape in relation to the target.


cutoff - this parameter specifies a threshold for the light intensity, below which the light will not be computed. This can be useful in scenes with many lights, where you want to limit the effect of the lights to some distance around them. Larger values cut away more from the light; lower values make the light range larger. If you specify 0.0, the light will be calculated for all surfaces.


shadow bias - bias moves the shadow toward or away from the shadow-casting object (or objects). If the Bias value is too low, shadows can "leak" through places they shouldn't, produce moire patterns or making out-of-place dark areas on meshes. If Bias is too high, shadows can "detach" from an object. If the Bias value is too extreme in either direction, shadows might not be rendered at all.


cast shadows - when on (the default), the light casts shadows. Turn this option off to disable shadow casting for the light.


affect diffuse - this determines whether the light is affecting the diffuse properties of the materials.


affect specular - this determines whether the light is affecting the specular of the materials.


use light shape - this option determines wether and how the the shape of the light specified in the .ies light will be taken into consideration during the calculation of shadows and illumination.


No - the light shape will not be considered for illumination and the light is going to generate sharp shadows.


For shadows - The light shape will be considered only for the generation of soft shadows. The illumination will not be affected by the light shape i.e. it will behave as a point light.


For illumination and shadows - the light shape will be considered for the calculation of the illumination and shadows.


override shape - when enabled the light profile is ignored and the shape parameter is used insted. The height, width, length and diameter parameters can be used to specify the dimensions of the light.


shape subdivs - this value controls the number of samples V-Ray takes to compute lighting. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time. Note that the actual number of samples also depends on the DMC Sampler settings.


Color mode - allows you to select the mode in which the color of the light will be determined:


Color - the light color is directly specified by the Color parameter.

Temperature - the light color temperature (in Kelvin) is specified by the Temperature parameter.


Color - when the Color mode is set to Color this parameter determines the color of the light.


Color temperature - when the Color mode is set to Temperature this parameter determines the color temperature (in Kelvin) of the light.


Power - determines the intensity of the light in lumens.

Area speculars - when this option is Off the particular light will be rendered as a point light in the specular reflections


Exclude - this button brings up the 3ds Max include/exclude button which allows the user to exclude objects from illumination and shadow casting.