Realistic Spotlights for Blender & Cycles

Software:
Blender 2.79 | Cycles Renderer

There’s currently no built-in support for IES light sources in Blender & Cycles.
We already know that Blender 2.8 will have the feature built into it (which is great news!), and there’s an addon that provides the functionality, but I wasn’t satisfied with it’s workflow, not being integrated well into Cycles.
So I decided to develop a custom Cycles shader (node group) that will provide realistic IES like spotlights in a convenient customizable way.

The Shader I developed is called CG-Lion Spotlight Presets Pack 1.0 and is available for purchase on Blender Market.
It doesn’t load external IES files, but instead has a pre-configured library of 20 spotlights shapes, and also provides features that are not available in IES lighting like tweaking the spotlight beam focus, adding a chromatic dolor dispersion effect, and producing a correctly bright surface at the light source.

CGL_Spotlight_Presets_Pack_1.0_Previews.jpg

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Related:
Customizable Photo-realistic Car-paint shader for Cycles
Complex Fresnel texture for Cycles

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IES Lighting in CG

IES stands for Illuminating Engineering Society, it is the organization responsible for creating and maintaining industrial standards for design and manufacturing of artificial light sources.

In 3D rendering, an IES file or “photo-metric file” is a text file containing a physical description of a light source’s beam spread , pattern and intensity, allowing for faithful depiction of the light source in 3D renders.
Most modern 3D rendering software support IES lights, that is allow loading IES files into the software and lighting the 3D scene using the light source described in the IES file.

Lighting manufacturers make measurements of their light fixture model’s physical light output and create IES files available for download on their websites.
This allows architects, lighting designers, and interior designers to download the files and realistically visualize the light sources effect on their projects.

CG artists use IES lights to add realistic spotlight beam patterns to their renderings and animations, such that can’t be created using regular simple 3D light sources.

Examples of IES lights rendered with V-Ray for 3ds max:

IES

Related:
IES Spotlights for Blender & Cycles

Maya – Setting the V-Ray Sun direction according to location, date and time

Software:
Maya 2018 | V-Ray 3.6

To set the VRaySun photometric light source diretion according to the location in the world, the date and the time:

  1. Select the VRaySun parent node – ‘VRayGeoSun1Transform‘ and rotate it so its Z axis points to the architectural plan’s south.
  2. Select the VRaySun node – ‘VRayGeoSun1‘ and in its attributes un-check Manual Position.
    This will make the location / date / time parameters accessible.
  3. Set the GMT zone of you architectural project’s location in the world, the Date and time.
    * haven’t found how to set daylight saving time….

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Related:
V-Ray for Maya Physical Camera
V-Ray for Maya White Balance
Daylight system addon for Blender

Cycles Light (Shadow) Sampling

Software:
Blender 2.79

By default, in Path Tracing Integrator Mode, Cycles traces one ray randomly between all lights (per each camera – AA sample).
So if some lights in the scene are more important than others this will cause inefficient light sampling.
* Especially if there are a few important lights and many unimportant ones.

Light sampling can be set per light by switching the Integrator Mode to Branched Path Tracing, making sure Sample All Direct Lights is checked, and the setting the number of samples per light in the light parameters.
* The option to set the number of samples at the light parameters is only available in Branched Path Tracing Mode.

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In the example below there are 3 lights.
The light on the right has 64 a samples per AA sample, while the 2 other lights have just 1 sample.

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More on Cycles sampling:
https://docs.blender.org/manual/en/dev/render/cycles/settings/scene/render/integrator.html#sampling