LIGHTING: Indirect Lighting with HDRI

If Arnold is not installed . . .

Turn on Arnold Render Windows > Settings/Preferences > Plug-in Manager
Scroll down to the bottom and then check both boxes next to mtoa.mll


Talk about indirect lighting. NOTES!
In our case, the main light source is in the ceiling. Look at the top your hand, why is the bottom of your hand not completely in the shadows?

Reflecting Light is a transverse, electromagnetic wave that can be seen by humans.

The photon is the basic "unit" of light.

Any light that you see is made up of a collection of one or more photons propagating through space as electromagnetic waves. In total darkness, our eyes are actually able to sense single photons, but generally what we see in our daily lives comes to us in the form of zillions of photons produced by light sources and reflected off objects. If you look around you right now, there is probably a light source in the room producing photons, and objects in the room that reflect those photons. Your eyes absorb some of the photons flowing through the room, and that is how you see.

For instance, a photon in the visible spectrum would contain an energy of approximately 4 X (10 to the power of -19) joules Thus, a perfectly efficient 100-watt light bulb would emit approximately 2.5 X (10 to the power of 20) photons per second.

First . . . Download a “Cool” HDRI file.

HDRI Images Sources

HDRI Image Source 1:

* I used this one for my test. 
Here is the scene with a basic 3-point lighting setup.
  • Arnold Render
  • Blin on Subject
  • Lambert Ground
Here is the same scene with a basic 3-point lighting setup and a .


Adding Image Based Lighting

To add a SkyDome Light choose the Arnold >Lights > Skydome Light


In the Atribute editor, select the checkerboard icon to the right of the color attribute and a new window will appear – Create Render Node.

In the Create Render Node window, select File.
In the Attribute Editor a new tab will appear.  Select the File Folder next to the Image Name and a new window opens.
Navigate to the HDRI image you want to use, selct it and select Open.

How to make GOLD

Right-click on the object and choose Assign New Material.  Select the Arnold render material options in the drop-down and choose aiStandard.

Right-click on the material you want to change and choose Material Attributes.

Here is a link to more materials:   

Diffuse Color (RGB) 0.831, 0.472, 0
Diffuse Weight 0.6
Diffuse Roughness
Specular Color (RGB) 1, 0.864, 0.68
(Specular) Weight 0.4
(Specular) Roughness 0.439
(Specular) Fresnel (Checkbox) on
(Specular) Reflectance at Normal
(Reflection) Color 1,1,1
(Reflection) Weight 0
(Reflection) Enable Internal Reflections on
(Reflection) Fresnel (Checkbox) off
(Reflection) Reflectance at Normal -
(Refraction) Color (RGB) 1,1,1
(Refraction) Weight 0
(Refraction)  IOR 1
(Refraction)  Roughness 0
(Refraction) Fresnel Use IOR off
Transmittance (RGB) 1,1,1
Emission Scale 0
SSS Color
SSS Weight