TECH ART SECTION LINKS

UE4 PBR MATERIAL OPTIONS FOR MAYA (developed in Python 2.7 with a MEL-based GUI)
The UE4 PBR Material Options tool was developed in Python/MEL for Maya and selection-based use. It allows artists to iterate faster on PBR content in Maya for a seamless integration into the UE4 environment. This tool can name/assign/create materials and delete unused ones without needing to open the Hypershade, import textures with a material auto-setup process, live/selection-based texture reloading, export meshes/textures into organized subdirectories for auto-reimporting into UE4, check/notify the user if the tool is being used in unsupported ways, and to calculate lightmap densities based on UE4’s Ideal Density value.
Below is a tech demo and sample Python/MEL code for the UE4 PBR Material Options tool. In addition, you can click and drag the code box's lower right-hand corner to expand it.

  # Imported modules.
  import maya.cmds
  import maya.mel as mel
  from sys import exit
  from glob import glob
  from os import path, remove, rename
  from shutil import copy2
  from math import sqrt

  for object in _meshSelection:

      # Gets the polygonal surface area in cm/world space.
      _surfaceArea = (cmds.polyEvaluate(object, worldArea=True))

      # Gets the square root of the surface area to convert it to a squared resolution.
      _sqrtSurfaceArea = (sqrt(_surfaceArea))

      # Converts the cm squared resolution to a m squared resolution.
      _meterStandard = (_sqrtSurfaceArea / _cmToM)

      # Gets the UE4 Ideal Lmap Density value for the mesh based off the polygonal surface area.
      _ue4IdealdLmapSurfaceAreaDen = (_meterStandard * (_idealLmapDenRatio * _userDensity))

      # Gets the names of all the UV sets for the current object.
      _uvSetNames = cmds.polyUVSet(object, query=True, allUVSets=True)

      # If the user chooses an UV set index value that's greater than what the current object contains, the object is skipped.
      if _userUvIndex > (len(_uvSetNames) - 1):
          _outOfRangeUvIndex.append(object)
          continue


UE4 CUSTOM VIEW MODES (developed in UE 4.22)
The UE4 custom view modes below help artists visually problem-solve different aspects of their materials and lighting. Some of the debug overlays are for out-of-range PBR values, nit/false color/roughness complexity heatmaps, Rec.709 broadcast legal levels, AO coloring, a zebra pattern function, film grain, and luminance visualizers for base color/focal point control.

SUBSTANCE DESIGNER PBR UTILITY NODES FOR UE4
These PBR utility nodes were designed to work within UE4's PBR range. Three of them use physically-based data for dielectric, metallic, and specular presets. Another validates whether your dielectric/metallic albedo values are within/outside UE4's PBR range, while the final PBR utility node can adjust out-of-range base colors.

UE4 NEUTRAL LIGHTING ENVIRONMENT (developed in UE 4.18)
The neutral lighting environment below uses all dynamic effects, like LPVs, DFAO, SSR, SSAO, RTDF, volumetric lighting, Convolution Bloom, bokeh lens flares, utilization of real-world data, etc., for quick material/asset testing without the need to bake lighting. The scene includes varying, physically-approximated TODs, tools, and PBR materials for visual reference. 

PBR ​LIGHTING GUIDE
  Section Links: Light Terms Guide | Light Values Guide | Color Temperature Guide | EV100 Guide | Sunny 16 Rule Guide

​Note: This guide assumes the reader has a basic understanding of PBR.

Generally, daytime lighting has a ~4:1 sun/sky (direct light vs shade) intensity ratio, sunrise/sunset is ~3:1, and overcast is ~2:1. However, since lighting conditions vary by location, time of day, weather, pollution/atmosphere, season, etc., the values listed below should only be used as a guide.

LIGHT TERMS GUIDE
TERM
DEFINITION
​Lumen
​Total emitted light.
Cd/m² or Nit
(cd = candela) Light source intensity per square meter.
Lux
Reflected surface illuminance. Also, 1 lux = 1 lm/m², or a 1 cd light at 1 m = 1 lux.
IRE
Video exposure unit.
Inverse Square Falloff
Describes physical light falloff. Also, intensity (cd) ∝ 1/square of the distance.
Energy Conservation
Reflected light is never brighter than its cast light.
Bidirectional Reflectance Distribution Function
(BRDF) Defines reflected light.
Direct Light
Light source light.
Indirect Light
Bounce light.
Ambient Light
Surrounding environment light.
Diffuse Light
Reflected surface light.
Key Light
Primary light source.
Fill/Helper Light
​Supplementary light used to brighten shadows/content and/or to simulate bounce light.
Rim Light 
​Light contouring subjects for background separation, thus implying depth.
Motivated Light
Light that simulates physical light sources, like a light bulb or window.
Unmotivated Light
Support light that doesn't have a physical representation.
High-Key Lighting
Bright, low-contrast lighting.
Low-Key Lighting
Dark, high-contrast lighting.
​Azimuth
Horizontal angle of the sun’s position.
Zenith
Vertical angle of the sun’s altitude.

LIGHT VALUES GUIDE
DESCRIPTION​
LIGHT CD/M² or NIT VALUES
​Brightest Sunlight
​​120,000 lux
Sunlight Range
30,000 - 120,000 lux
Bright Sunlight​​
111,000 lux
White Paper at Sunny Noon
25,000 cd/m²
Clear, Midday Shade
​20,000 lux
​Fluorescent Lights
12,000 cd/m²
Brightest, White Clouds
​​10,000 cd/m²
Average, Clear Sky
​​5,000 - 7,000 cd/m²
Midday Overcast
​1,000 - 2,000 lux
HDR10 LCD Monitor
​1,000 cd/m²
Clear Sunrise/Sunset ​​​
400​​​ lux
​LCD Monitor Peak Luminance
250 cd/m²
Thickest, Midday ​Storm Clouds ​​
​< 200​ lux
sRGB Reference Monitor White​
80 cd/m²
Sunrise/Sunset Overcast
40 lux
Floodlit Buildings
​​2 cd/m²
Thickest Sunrise/Sunset Storm Clouds ​​​​
< 1​​​​​​​​ lux
Clear Night with Full Moon
0.25 lux
Clear Night with Quarter Moon
​0.01​ lux
Clear, Moonless Night with Airglow
0.002​​ lux
Clear, Moonless Night
0.0002​​ lux
Moonless Night Overcast
0.0001 lux

COLOR TEMPERATURE GUIDE
​Color temperature (K) is defined by the temperature of a blackbody emitting light with a particular color. Blackbodies also absorb all light casted onto them.

 Below are color temperature examples with values listed in sRGB first with corresponding sRGB color swatches. 
DESCRIPTION​
COLOR TEMPERATURE
COLOR SWATCH
​HEXADECIMAL VALUES
​RGB CHANNEL VALUES
​NORMALIZED VALUES
Clear, Blue Sky
10,000+
sRGB = cfdaff
​Linear RGB = 9fb3ff
sRGB = (207, 218, 255)
​Linear RGB = (159, 179, 255)
sRGB = (0.812, 0.855, 1)
​Linear RGB = (0.624, 0.702, 1)
Hazy Sky
8,000
sRGB = e5e9ff
​Linear RGB = c8d0ff
sRGB = (229, 233, 255)
Linear RGB = (200, 208, 255)​
sRGB = (0.898, 0.914, 1)
​Linear RGB = (0.784, 0.816, 1)
​Outdoor Shade
7,000 - 8,000
-
sRGB = f7f5ff - e5e9ff
​Linear RGB = eee9ff - c8d0ff
sRGB = (247, 245, 255) -
​(229, 233, 255)
Linear RGB = (238, 233, 255) - (200, 208, 255)
sRGB = (0.969, 0.961, 1) - (0.898, 0.914, 1)
​Linear RGB = (0.933, 0.914, 1) - (0.784, 0.816, 1)
Daytime Overcast
6,000 - 7,000
-
sRGB = fff4ed - f7f5ff
​Linear RGB = ffe7d8 - eee9ff
sRGB = (255, 244, 237) -
​(247, 245, 255)
​Linear RGB = (255, 231, 216) - (238, 233, 255)
sRGB = (1, 0.957, 0.929) - (0.969, 0.961, 1)
​Linear RGB = (1, 0.906, 0.847) - (0.933, 0.914, 1)
LCD Monitor
6,500
sRGB = fff9fb
​Linear RGB = fff2f6
sRGB = (255, 249, 251)
​Linear RGB = (255, 242, 246)
sRGB = (1, 0.976, 0.984)
​Linear RGB = (1, 0.949, 0.965)
​Noon and Camera/Studio Flash
5,500
sRGB = ffeede
​Linear RGB = ffdaba
sRGB = (255, 238, 222)
​Linear RGB = (255, 218, 186)
sRGB = (1, 0.933, 0.871)
​Linear RGB = (1, 0.855, 0.729)
​Early Morning/Evening - Afternoon
3,500 - 5,000
-
sRGB = ffc987 - ffe7cc
​Linear RGB = ff953e - ffcc9a
sRGB = (255, 201, 135) -
​(255, 231, 204)
​Linear RGB = (255, 149, 62) - (255, 204, 154)
sRGB = (1, 0.788, 0.529) -
​(1, 0.906, 0.8)
​Linear RGB = (1, 0.584, 0.241) - (1, 0.8, 0.604)
Fluorescent Lights 
​4,000 
sRGB = ffd5a1
​Linear RGB = ffaa5b
sRGB = (255, 213, 161)
​Linear RGB = (255, 170, 91)
sRGB = (1, 0.835, 0.631)
​Linear RGB = (1, 0.667, 0.357)
1-hour After Sunrise/Before Sunset
3,500 - 3,600
-
sRGB = ffc987 - ffcb8d
​Linear RGB = ff953e - ff9844
sRGB = (255, 201, 135) -
(255, 203, 141)
​Linear RGB = (255, 149, 62) - (255, 152, 68)
sRGB = (1, 0.788, 0.529) -
(1, 0.796, 0.553)
Linear RGB = (1, 0.584, 0.243) ​- (1, 0.596, 0.267)
​Studio/Photoflood Lamps and Tungsten Lights
​3,200
sRGB = ffc076
​Linear RGB = ff862e
sRGB = (255, 192, 118)
​Linear RGB = (255, 134, 46)
sRGB = (1, 0.753, 0.463)
Linear RGB = (1, 0.525, 0.18)​
​Sunrise/Sunset
1,850 - 3,100
-
sRGB = ff8500 - ffbd6f
​Linear RGB = ff3c00 - ff8228
sRGB = (255, 133, 0) -
(255, 189, 111)
​Linear RGB = (255, 60, 0) - (255, 130, 40)
sRGB = (1, 0.522, 0) -
(1, 0.741, 0.435)
Linear RGB = (1, 0.235, 0) -
​(1, 0.51, 0.157)
​Halogen Lights
3,000
sRGB = ffb969
​Linear RGB = ff7c24
sRGB = (1, 185, 105)
​Linear RGB = (255, 124, 36)
sRGB = (1, 0.725, 0.412)
​Linear RGB = (1, 0.486, 0.141)
​Incandescent Lights
2,400 2,800
-
sRGB = ffa23c - ffb25b
​Linear RGB = ff5c0b - ff711a
sRGB = (255, 162, 60) -
(255, 178, 91)
Linear RGB = (255, 92, 11) - (255, 113, 26)​
sRGB = (1, 0.635, 0.235) -
(1, 0.698, 0.357)
​Linear RGB = (1, 0.361, 0.043) - (1, 0.443, 0.102)
High-Pressure Sodium Lights
2,200
sRGB = ff9829
​Linear RGB = ff5005
sRGB = (255, 152, 41)
​Linear RGB = (255, 80, 5)
sRGB = (1, 0.596, 0.161)
​Linear RGB = (1, 0.314, 0.02)
Candle Flame
1,850
​◼
sRGB = ff8500
​Linear RGB = ff3c00
sRGB = (255, 133, 0)
​Linear RGB = (255, 60, 0)
sRGB = (1, 0.522, 0)
​Linear RGB = (1, 0.235, 0)
Match Flame
1,700 - 1,800
-
sRGB = ff7c00 - ff8200
​Linear RGB = ff3300 - ff3900
sRGB = (255, 124, 0) -
(255, 130, 0)
​Linear RGB = (255, 51, 0) - (255, 57, 0)
sRGB = (1, 0.486, 0) -
(1, 0.51, 0)
Linear RGB = (1, 0.2, 0) -
​(1, 0.224, 0)
Low-Pressure Sodium Lights
​1,700
sRGB = ff7c00
​Linear RGB = ff3300
sRGB = (255, 124, 0)
Linear RGB = (255, 51, 0)
sRGB = (1, 0.486, 0)
​Linear RGB = (1, 0.2, 0)

EV100 GUIDE
The combination of the aperture, shutter speed, and ISO define the exposure value. Below is an EV100 formula and guide.
​EV100 FORMULA​
Note: ​Shutter Speed = (1 / Time) = Fraction of a Second
EV100 = ( log2(Aperture² / (Shutter Speed) * 100 / ISO) )
DESCRIPTION​
EV100​
​Bright Sunlight on Sand/Snow (distinct shadows)
16
​Clear, Bright Sunlight (Sunny 16 Rule/distinct shadows)
​15
Hazy Sunlight (soft shadows)
​14-15
​Before Sunset
​12-14
Bright and Cloudy (no shadows)
​13
​Overcast and Shade with Clear Sunlight
​12
Sunset
​11-12
After Sunset
​9-11
​Galleries
​8-11
​Neon/Bright Signs
9-10
​Sport Events and Stage Shows
​8-9
​Bright Streets, Window Displays, and Office Spaces
7-8
Rainforests
​7
​Fairs and Amusement Parks
6-7
​Home Interiors
5-7
​Night Traffic
5
Christmas Lights
4-5
Floodlit Buildings
​3-5
​Street Lamps and Candle Close-ups
4
Fireworks
3
Lightning
​2
​Distant, Lit Skylines
​1-2

SUNNY 16 RULE GUIDE
​The Sunny 16 Rule, which can be viewed in the chart below, approximates correct daylight exposures without a light meter. The camera's ISO and shutter speed share a reciprocal relationship. 
ISO
SUNNY - f/22
(sand/snow)
SHUTTER SPEED
SUNNY - f/16
​(strong shadows​)
SHUTTER SPEED
PARTLY CLOUDY - f/11
(soft shadows)
SHUTTER SPEED
CLOUDY - f/8
(faint shadows)
SHUTTER SPEED
CLOUDY - f/5.6
(no shadows)
SHUTTER SPEED
SUNSET - f/4
(long shadows)​
SHUTTER SPEED
100
1/100 or 1/125
1/100 or 1/125
1/100 or 1/125
1/100 or 1/125
1/100 or 1/125
1/100 or 1/125
200
1/200 or 1/250
1/200 or 1/250
1/200 or 1/250
1/200 or 1/250
1/200 or 1/250
1/200 or 1/250
400
1/400 or 1/500
1/400 or 1/500
1/400 or 1/500
1/400 or 1/500
1/400 or 1/500
1/400 or 1/500
800
1/800 or 1/1,000
1/800 or 1/1,000
1/800 or 1/1,000
1/800 or 1/1,000
1/800 or 1/1,000
1/800 or 1/1,000

UE4 PBR LIGHTING GUIDE (requires UE 4.21+)
  Section Links​: UE4 Real-time Ray Tracing Guide | ​The Matted, White Paper Test | UE4 Cubemap Orientation Guide

Note: UE4 Real-time Ray Tracing Guide subsection links can be found in the beginning of that guide.

  Subsection Links​: Lights | Fog | Sky | Manual Exposure | Auto-exposure | HDR Histogram | Pre-exposure | Materials | Tonemapper

Note: This guide assumes the reader has a basic understanding of PBR.

​•  Sun: Uses lux values with an angular diameter of 0.5357. You can apply Light Values Guide and Color Temperature Guide data to sun Intensity/Temperature parameters.
Note: ​If you’re trying to align the sun’s location to one in a skybox texture, you can use the UE4’s BP_Sky_Sphere to assist you. This can be achieved by either adjusting the sun’s position to match the skybox’s sun or by rotating the skybox itself. By toggling the visibility of the BP_Sky_Sphere, making sure you have the correct directional light actor assigned to it, and refreshing its material to update its procedural sun texture whenever you make sun rotational changes, can this process then visually help you align the sun to the skybox’s sun. Techniques for skybox setup can be found in either The Matted, White Paper Test or UE4 Cubemap Orientation Guide sections.
The Sun Position Calculator renders geographically accurate sun location, date, and time of day. To use the BP_SunPosition, a BP_Sky_Sphere is required to move the sun disk and orient the Directional Light (It also needs to be assigned to the BP_Sky_Sphere.), which should be set to Moveable for dynamic sun angle change. Additionally, the BP_SunPosition gizmo's (seen below) rotation property should not be modified, as this attribute is driven by its North Offset parameter.
Below are BP_SunPosition attributes and their descriptions.
ATTRIBUTE
DESCRIPTION
​Latitude
Positive values are east of the prime meridian, while negative ones are west of it.
​Longitude
Positive values are north of the equator, while negative ones are south of it.
Time Zone
Offsets the hour amount from UCT/GMT.
North Offset
Rotates the BP_SunPosition's orientation.
​Date and Time
Sets the time of year/day. Options include year, month, day, daylight-saving time, hour, minute, and second.
•  Sky: Uses cd/m²​, or nit, values. The sky luminance is determined by the HDRI's pixel intensity values multiplied against the Sky Light's Intensity parameter. You can apply Light Values Guide data to sky intensity values.

Note: The Pixel Inspector (Window > Developer Tools > Pixel Inspector) can analyze scene pixels for sky intensity values via its HDR Luminance reader. (This method can be used to standardize emissive texture values.) 

•  Spot/Point/Rect Lights: Uses unitless, candela, or lumen values. (The light must have Inverse Squared Falloff enabled to specify the light unit. When disabled, low-intensity fill/helper lights can be used when hot spots near light sources are undesired.) You can apply Light Values Guide and Color Temperature Guide data to lights' Intensity/Temperature parameters.

Note: The default light unit can be set in the Project Settings. (
Project Settings > Rendering > Light Units) However, this can be overridden on a per-light level in the Details panel. Also, when using candelas units, cone angle does not affect the light's intensity. The opposite is true when using lumen values. (The smaller the cone angle, the stronger the surface illuminance intensity.)
Below defines the relationships between light types and physical light unit formulas used in UE4.​
UNIT TYPE
FORMULAS
​General Units
Note: sr = Steradians
1 cd = 625 Unitless Values
​1 cd = 1 lm/sr
Point Lights
Solid Angle = (4π sr)
Illuminance (1 lm) ≈ ( 49.7 * Illuminance (1 Unitless Value) )
​Illuminance (1 cd) ≈ ( 12.6 * Illuminance (1 lm) )
Spot Lights
Solid Angle = ( 2π * (1 - cos(θ)) ) and θ = Light Cone Half Angle
​Illuminance (1 lm) ≈ ( 99.5 / (1 - cos(θ)) * Illuminance (1 Unitless Value) )
​Default Spot Light Cone
Solid Angle ≈ 1.76 sr and θ = 44°
Illuminance (1 lm) ≈ ( 354 * Illuminance (1 Unitless Value) for a Default Spot Light )
​Illuminance (1 cd) ≈ ( 1.76 * Illuminance (1 lm) for a Default Spot Light )
Rect Lights
Solid Angle = (2p sr)
Illuminance (1 lm) ≈ ( 199 * Illuminance (1 Unitless Value) )
​Illuminance (1 cd) ≈ ( 3.14 * Illuminance (1 lm) )
Note: Using the r.Shadow.FilterMethod console variable with a value of 1, enables PCSS Shadows. This shadow type uses shadow maps but it does not utilize the default PCF filter. While PCSS Shadows are not physically-correct, they soften with distance from the shadow caster.

  ​​Emissive materials: Uses cd/m2 for pixel luminance. This is utilized by emissive materials (Materials set to Unlit in the Material Editor.) applied to static meshes with their Use Emissive for Static Lighting setting enabled. The Emissive Boost property scales the static light intensity emitted from the emissive material. This can also be achieved by multiplying an emissive texture against a value in the Material Editor. You can apply Light Values Guide and Color Temperature Guide data to emissive values.
  ​Volumetric Fog can be used by adding an Exponential Height Fog to your scene and enabling its Volumetric Fog option. It’s recommended whenever you are roughing in your scene’s lighting, always start with sun, sky, and fog elements due to their relationship to one another.
​For lights to interact with Volumetric Fog, you need to enable/adjust their Volumetric Scatter Intensity and Cast Volumetric Shadow parameters. Movable/stationary lights yield higher-resolution results with Volumetric Fog than static lights/volumetric lightmaps.
Note: Atmospheric Fog simulates scattered light through the atmosphere. It can be layered with Volumetric Fog (close-up fog) and used for fog fx near the horizon.

  To set/measure the sky's average luminance in cd/m², or nits, sample sky intensity values from midtone areas via the Pixel Inspector. Since reading individual pixels can vary, it’s best to average large portions of pixel values first for easier sky analysis. This can be achieved by loading the sky texture into the Texture Properties Editor, lowering its resolution or by increasing its mip level, saving it, and then analyzing the lower-resolution sky in the viewport. Techniques for adjusting sky intensity values  can be found in The Matted, White Paper Test section.
​Below is an example of an adjusted sky texture’s mip level. The one on the left has a resolution of 4,096 x 2,048 (mip level: 0), and the one on the right has a resolution of 32 x 16. (mip level: 7) It's important to note that each lower mip map level is half the resolution as its previous one.
NoteSky Lights capture scenes in a cubemap format for ambient lighting and reflection contributions. (The lowest mip map level of a cubemap is used for ambient lighting, while the higher levels are for reflections/roughness textures.) You can add color to the lower hemisphere of your environment light by enabling the Lower Hemisphere is Solid Color option and adjusting the Sky Light’s Lower Hemisphere Color parameter. This can be used to simulate the average, reflected ground light/color. You can also leave the color black to only have ambient light cast from the upper hemisphere. (Sky color controls exterior shadow color.) This method allows baked bounce light to be more accurate for local, reflected ground light/color.
  Physically-based camera exposure can be controlled by the EV100 editor overrides, which is located in the viewport's Lit menu. If you choose to use it, uncheck the Game Settings first. You can apply EV100 Guide data to EV100 editor override values.
For additional control over physical camera attributes, you can use the Post Process Volume’s camera parameters. (Post Process Volume > Lens > Exposure > Metering Mode: Manual – the Camera options then become active.) It’s advised to leave the tonemapper alone unless you're trying to mimic a specific film stock. Further, you can apply Sunny 16 Rule Guide data to the Manual metering mode.
Below are physical camera properties and their descriptions.
ATTRIBUTE
DESCRIPTION
​Aperture
 Controls the amount of light that enters the camera via its opening size, as well as depth of field.
​Shutter Speed
T​he length of time film is exposed to light, which also determines motion blur amounts.
ISO
The camera sensor's sensitivity to light.
  Auto-exposure targets an average scene luminance equal to the Constant Calibration value, and it's histogram-based. Since there are different versions of eye adaptation, the following information covers a few of these options.
 
In the Post Process Volume, you can enable the Metering Mode to Auto Exposure Basic (Post Process Volume > Lens > Exposure > Metering Mode: Auto Exposure Basic) and still use UE4's PBR lighting system. For scenes that contain much higher luminance ranges, it’s recommended to switch to Min/Max EV100 settings (Edit > Project Settings > Rendering > Default Settings > Extend default luminance range in Auto Exposure settings) for proper auto-adjustments. (Min/Max EV100 replaces the Min/Max Brightness options in the Post Process Volume.) You can apply EV100 Guide data to Min/Max EV100 values. Below are common exposure properties these two methods share.
ATTRIBUTE
​DESCRIPTION
​Exposure Compensation
Adds stops (2^ExpComp) onto the set exposure.
Min/Max Brightness
​The clamped range the camera auto-adjusts within. By default, it uses cd/m², unless Min/Max EV100 is enabled.
Speed Up
Dark-to-light exposure adaption.
​Speed Down
Light-to-dark exposure adaption.
​Calibration Constant
Targets an average scene luminance (18%-albedo) and is used for white balancing.
Note: When Min Brightness = Max Brightness, auto-exposure is disabled. By increasing or decreasing the exposure by 1-stop, the brightness will either be doubled or halved. Moreover, sunny scenes typically work better with larger exposure ranges, while cloudy environments use smaller ones due to more evenly diffuse lighting. 
The HDR Histogram, expressed in EV100, is used by the auto-exposure to adapt the camera to the scene's luminance range. (Show > Visualize > HDR (Eye Adaptation)) 
Note: If Pre-exposure (Project Setting > Engine > Rendering > Apply Pre-exposure before writing to the scene color) is enabled, previous frame scene exposure is applied to the shaders. This is beneficial for bright lights and increased Auto Exposure Basic quality.

Note: The Pixel Inspector can analyze pre-exposure values.
  Since light calculations occur in linear color space, it’s advised to sometimes view sRGB albedo textures in this format to better understand how base colors impact lighting. (Typically, linear values are darker than sRGB ones.) For example, linear albedo values that appear too dark may not bounce enough light due to its high-absorption properties, thus potentially flattening baked lighting results. Inversely, linear albedo values that are very bright may reflect too much indirect light, creating a scene that could be hard to balance. (Most dielectric albedo colors exist in the sRGB midtones, while a majority of metallic albedo colors reside in the 218-255 sRGB range.) Finally, albedo values that are too saturated may scatter overly-colored bounce light, rendering a potentially undesirable look. You can visit the Albedo Luminance Range section for more information on suggested PBR base color value ranges. Below are other material properties to consider regarding light interactivity.
MATERIAL
DESCRIPTION
Transparent
Low-absorption and no scattering.
Translucent
Low-absorption and high-scattering.
Opaque
High-absorption or reflectance and low-scattering.
Note: UE4 uses the ACES Filmic Tonemapper to help map HDR values and wide color gamuts to LDR displays, and to future-proof content. While using the tone mapping function, visuals obtain higher-quality and more realistic results. For instance, as colors become more desaturated the brighter it gets, there's a reduction of flattened highlights, a greater use of contrast range, and shading/color is better preserved. (For comparative purposes, you can enable/disable the ACES Tonemapper by going to the Viewport > Show > Post Processing > Tonemapper.) In addition, the Rec.709 color profile is UE4’s default viewing space for LDR displays so that it can match broadcast standards used by console games.

UE4 REAL-TIME RAY TRACING GUIDE (requires UE 4.22+)
  Subsection Links​: System Requirements | RT Components | Path Tracer | Post Process Volume RT Options | RT Shadow Attributes | General Optimization Tips and Tricks | Console Variables | Denoiser

UE4 real-time ray tracing supports shadows, reflections, translucency, ambient occlusion, and global illumination with a hybrid rendering approach. (Ray tracing/rasterization mix.)
  System Requirements

o Windows 10, Build 1809 or above
o DXR-compatible GPU (Nvidia RTX/GTX)
o UE 4.22 or above
In the UE4 Project Settings, the following attributes need to be enabled:
o Platforms > Windows > Default RHI > DirectX 12
o Engine > Rendering > Ray Tracing (Support Compute Skincache must also be enabled.)
  The guide below outlines each of the real-time ray tracing (RTRT) components.
RT COMPONENT
DEFINITION
Global Illumination (RTGI)
Diffuse component of bounce light.
Reflections (RTR)
Specular component of bounce light for whole-scene/inter-reflections.
Translucency (RTT)
Reflection, absorption, and refraction properties for transparent surfaces.
Ambient Occlusion (RTAO)
Blocked indirect light.
Shadows
Soft area shadows. Light size/source angle increases shadow softening over distance.
From left to right, are images of RTGI increasing in bounce amount.

Note: When RTGI is enabled, its settings and Denoiser, override the RTAO parameters. In addition, increased RT bounces cost more on performance.
From left to right, are images of RTR increasing in bounce amount.
  For quicker iteration time, the built-in path tracer renders unbaised, progressive, physically-based ground truth reference to compare/validate the real-time, ray traced results. It can be enabled via the Viewport > Lit > Path Tracing.
  The Post Process Volume contains many high-level parameters to control RT. (Post Process Volume > Details > Rendering Features) You can add more Post Process Volumes to a scene and determine which RT features are important for specific areas, like interior vs exterior spaces. The image below displays the various Post Process Volume RT attributes.
The guide below outlines the Post Process Volume RT attributes. 
RT COMPONENT
ATTRIBUTE
DEFINITION
All
Samples Per Pixel
Number of samples per pixel.
RTGI/RTR/Path Tracer
Max Bounces
Maximum number of bounces for light/inter-reflections.
RTR/RTT
Type
Determines if RT or SSR/rasterized translucency is used.
RTR/RTT
Max Roughness
Roughness threshold for RT/rasterized methods.
RTR/RTT
Shadows
Sets reflected shadows to be hard, soft, or disabled.
RTAO
Intensity
RTAO intensity in indirect light.
RTAO
Radius
RTAO spread in UE4 units.
RTGI
Enabled
Enables/disables RTGI.
RTT
Max Refraction Rays
Maximum number of refraction rays.
RTT
Refraction
Toggles RT Translucency. If disabled, rays will not scatter.
  RT Shadow attributes are controlled by light sources.
The guide below lists the RT Shadow attributes.
LIGHT TYPE
ATTRIBUTE
DEFINITION
All Lights
Cast Raytraced Shadow
Sets the light to use RT shadows or shadow maps.
All Lights
Affect Reflection
Determines if the light affects objects in RT reflections.
All Lights
Samples Per Pixel
Number of samples per pixel for RT shadows.
Sun
Source Angle
Angular diameter. Smaller angles = sharper shadows. Larger angles = softer shadows.
Point/Spot
Source Radius
Smaller radius = sharper shadows. Larger radius = softer shadows.
Rect
Source Width/Height
Smaller values = sharper shadows. Larger values = softer shadows.
Rect
Barn Door Angle/Length
Shapes/softens shadows.
Note: Unless specified, RT Shadows can be drawn from an infinite distance. And, the larger the light's source angle/radius/size, the more expensive RT Shadows become.
  Below are general optimization tips and tricks for real-time RT.

o From cheapest to most expensive RT components: shadows, RTAO, RTR, and then RTGI. (Secondary/additional bounces can be more expensive than the first one due to more surface variance interactions.)

o For optimization, both RT and lightmap/rasterization techniques can be combined.

o Material complexity, as well as opacity masks, can impact RT performance. With the Material Editor's RayTracingQualitySwitch node (It supports RTR, RTT, and RTGI.), simplified representations of material graphs can be used for RT hit shaders. In addition, actors have a Visible in Ray Tracing option (Actor > Details > Rendering > Visible in Ray Tracing) to determine whether it gets calculated for RT or not.
 o Using master materials with a few instances is cheaper on RT than having many shader permutations. (The fewer the shaders, the cheaper real-time RT becomes.)

o RTGI can be more expensive for interiors (More indoor bounces can occur, while outdoor rays discontinue once they exit the scene toward the sky. Not to mention directly lit areas render faster than indirect spaces, and larger scenes work better for RT than rasterized techniques.) than exteriors. Detailed geometry, or small holes/spaces (Vegetation or fences, for example.), can affect performance. Larger, geometric shapes work better.

o RTR is best suited for glossy reflections for accuracy and its cost can vary greatly based on roughness values. Fully-rough materials are the cheapest (They do not bounce reflection rays. Instead, they rely on cheaper, rasterized reflection techniques.), followed by fully-glossy surfaces (When rays bounce in the same direction, via ray coherency or a lack of ray variance, they become cheaper to calculate.), then near fully-glossy, and finally, roughness values around 0.5 to near fully-rough, being the most expensive. (The more ray traversal variance/noise, the more expensive.)

Note: No assigned roughness map/value is more expensive than setting it to a value of 1. By default, UE4 treats the roughness material property with a value of 0.5. And for optimal performance, either fully-rough or fully-glossy values work best for RTR. Additionally, controlling the RTR’s Max Roughness attribute can help optimize a scene by setting a threshold for the RTR effect.

o Shadowing is usually the most expensive reflection component, followed by direct light, and then indirect light/emissive surfaces.

o Like roughness textures, normal maps can impact RT costs due to bounce variance from differing pixel normal values. The more intense the normal map, the more expensive RT becomes.

o Minimize RT inter-reflections, as they can require multiple bounces.
o RT shadows can perform better than cascaded/dynamic shadow maps (This is due to RT being less sensitive to polycounts than rasterized techniques.), especially for outdoor environments. (Bounding volume hierarchies are used to minimize ray intersection tests.)
  The guide below is not designed to be a comprehensive list of all the RT console variables. Instead, it provides a collection of some features to help optimize and control a scene. High-level parameters available in the UI (Post Process Volume, light sources, actors, etc.) are not listed.

Note: [0|1] values are used for each console variable unless stated otherwise.
CONSOLE VARIABLE
DEFINITION
r.RayTracing.EnableMaterials
Toggles materials for RT and to test material cost.
r.RayTracing.Reflections.ScreenPercentage [50|100]
Changes RTR resolution by a %.
r.RayTracing.GlobalIllumination.ScreenPercentage [25|50|100]
Changes RTGI resolution by a %.
r.RayTracing.GlobalIllumination.EvalSkylight
Toggles sky light RTGI.
r.RayTracing.Reflections.MinRayDistance [0-N]
Min RTR distance. (scene units) Rays that terminate before surface contact sample the sky.
r.RayTracing.Reflections.MaxRayDistance [0-N]
Max RTR distance. (scene units) Rays that terminate before surface contact sample the sky.
r.RayTracing.GlobalIllumination.MaxRayDistance [0-N]
Max RTGI distance. (scene units) Rays that terminate before surface contact do not contribute.
r.RayTracing.Reflections.HeightFog
Toggles Height Fog visibility in RTR.
r.RayTracing.Shadows.EnableTwoSidedGeometry
Toggles two-sided geo for RT shadows.
r.RayTracing.AmbientOcclusion.EnableTwoSidedGeometry
Toggles two-sided geo for RTAO.
r.RayTracing.SkyLight.EnableTwoSidedGeometry
Toggles two-sided geo for Sky Lights.
r.RayTracing.DebugForceOpaque
Toggles alpha masking.
r.RayTacing.Reflections.SortMaterials
Sorts RTR rays based on material coherence. There is an overhead cost, so performance may vary.
Note: Console variables can be implemented into the scene's Level Blueprint (Or via .ini files.) so they don’t have to be manually set up from the console. In the Level Blueprint, console variables can be added to Execute Console Command nodes.
  From left to right, are examples of the Denoiser and TAA filtering RT samples.
Currently, the Denoiser supports only 1 spp. While this process leads to some information loss, the results are comparable to non-denoised, multiple ssp, like in the images below.

THE MATTED, WHITE PAPER TEST ​(developed in UE 4.20)
To confirm the accuracy of UE4’s PBR lighting system without adjusting the Sky Light’s Intensity parameter, I created a simple scene to evaluate it with the Pixel Inspector. This test uses physical values of matted, white paper and real-world data for sun/sky intensities. You can click on the gallery images below to learn more about this process.

UE4 CUBEMAP ORIENTATION GUIDE (for custom-cubemapped skyboxes)
​Cubemap panels need to be arranged in a specific manner for correct orientation in UE4. The chart below represents these panels in a horizontal strip format, ordered from left to right, as you go down the list. 
AXIS
ROTATION
+X
90° CCW
-X
90° CW
+Y
180°
-Y
No Rotation
+Z
No Rotation
-Z
No Rotation
Note: Alternatively, you can import a 32-bit OpenEXR sky texture with an equirectangular, 2:1 aspect ratio, use it within a material, assign it to a sphere covering the whole background, and then capture the results in a cubemap via the Sky Light. Techniques for skybox setup can be found in The Matted, White Paper Test section.

​​GENERAL TEXTURING GUIDE
  Section Links: Texture Type GuideEdge Padding Guide​

​Note: This guide assumes the reader has a basic understanding of PBR.

TEXTURE TYPE GUIDE
It’s important that textures are interpreted in the correct color space, so below is a guide to help with this process.
MAP
DESCRIPTION
# OF CHANNELS
COLOR SPACE
Albedo
Base colors with no lighting/spec/shading data. Most albedo values exist in the midtones.
3 | RGB
sRGB
Normal
Baked, high-res surface detail with vector directionality data for direct light interaction.
3 | RGB
Linear RGB
AO​
Blocks ambient light.
1 | Grayscale
Linear RGB
​Cavity
​Micro-ambient occlusion. 
1 | Grayscale
Linear RGB
​Height
​Surface elevation information.
1 | Grayscale
Linear RGB
Metallic
​Determines if a material is a metal, dielectric, or a mix. 
1 | Grayscale
Linear RGB
Opacity
Transparency.
1 | Grayscale
Linear RGB
​Roughness
​Defines reflective surface properties. 
1 | Grayscale
Linear RGB
Transmissive
​Controls scattered light passing through a surface.
1 | Grayscale
Linear RGB
Note: Channel packing multiple grayscale maps into one texture can save on memory cost.

EDGE PADDING GUIDE
Proper edge padding can minimize color bleeding artifacts from mip mapping. The chart below displays different texture resolutions with corresponding edge padding values for UV shell spacing and downsizing of textures.
TEXTURE RESOLUTION
EDGE PADDING VALUES
256 x 256
2px
512 x 512
4px
1,024 x 1,024
8px
2,048 x 2,048
16px
4,096 x 4,096
≥ 16px

UE4 PBR MATERIAL GUIDE (requires UE 4.20+)
  Section Links: Albedo Luminance Range | Metallic Range | Roughness Range | Specular Guide | Index of Refraction Guide | Clear Coat GuideGrays Guide | Gamma Conversion Guide | Dielectric Albedo Values Guide | Metallic Albedo Values Guide | Albedo L​uminance Guide | Albedo S​aturation % ​Guide

Note: This guide assumes the reader has a basic understanding of PBR.

​UE4 supports the metallic/roughness PBR workflow. Some of the values listed below work best in UE4 and may not be suited for other applications. Further, UE4's environment and color picker live in linear color space, but artists typically work in sRGB. In effect, the following values are in sRGB first with corresponding sRGB color swatches. 

Albedo LUMINANCE range

MATERIAL
DESCRIPTION
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
NORMALIZED VALUES
Charcoal 
Dielectric albedo values control reflected color and most exist in the midtone range. Charcoal is the darkest dielectric albedo value that should be used. Insulators don't typically have colored specular reflectivity, but lights affect reflected color.
​​sRGB = ​​2b2b2b
Linear RGB = 
060606
​​sRGB = ​43
Linear RGB = 
​5
​​sRGB = ​0.17
Linear RGB = 
​​​0.02
Fresh Snow 
Dielectric albedo values control reflected color and most exist in the midtone range. Fresh snow is the brightest dielectric albedo value that should be used. Insulators don't typically have colored specular reflectivity, but lights affect reflected color.
​​sRGB = ​​e8e8e8​
Linear RGB = cecece
​​sRGB = ​232
Linear RGB = 
​207
​​​sRGB = ​0.91
Linear RGB = 
0.81
Metallic
Unlike dielectric base colors, metallic albedo brightness controls specular intensity, which can contain color. Conductive albedo values fall within this row’s range. 
-◼
​sRGB = d9d9d9​ - ffffff
Linear RGB = b1b1b1 - ffffff
​​sRGB = 217 - 255
Linear RGB = 179 - 255
​sRGB = 0.85 - 1
Linear RGB = 0.7 - 1


Metallic Range

MATERIAL
DESCRIPTION
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
NORMALIZED VALUES
Dielectric
On average, most dielectrics have a F0 value of 4% reflectivity and do not require a metallic map. If they are part of an asset that needs one, the non-metal portions should be black. Further, metallic map properties should represent the top layer of the material, like painted metal, which would not be metallic in this case.
​sRGB = 000000
Linear RGB = 000000

​sRGB = 0
Linear RGB = 0

​​sRGB = 0
Linear RGB = 0

​Metallic
This map determines whether the albedo map is treated as reflected color or metallic reflectance values. Most metals have a value of 1, and the metallic map is multiplied against the base color texture. You can have gradient transitions between insulators and conductors. Exceptions, like metalloids, may use values that are neither 0 or 1.
​​sRGB = ffffff
Linear RGB = ffffff

​​sRGB = 255
Linear RGB = 255

​​sRGB = 1
Linear RGB = 1

The images below display ​increasing dielectric-to-conductor metallic properties.

Roughness Range

The roughness map controls size/spread, sharpness, and light direction for rough/smooth reflective surface attributes. Real-world data is not used for its rendering, thus allowing for more artistic interpretation. The images below display increasing rough-to-glossy properties for both dielectric (top row) and metallic materials. (bottom row)
Note: Roughness and normal maps are used to describe micro/macro surface detail. Additionally, Composite Textures can help reduce specular aliasing and shimmering of normals maps by combining them with roughnesss maps, creating brighter, more matted roughness map variants.

Specular GUIDE

UE4’s specularity has a default value of 0.5, or 4% reflectance, to represent common dielectrics. (Metals are not affected by this property since their albedo maps control specular strength.) However, more unique materials, like semiconductors and gemstones, can be higher. Since all surfaces have some level of specular reflectivity, this property should never be set to 0. You can connect cavity maps to it, but they should first be multiplied against the default 0.5 value. This is for consistency with UE4’s average dielectric F0 reflectance value, while removing specularity in baked, micro-occluded areas.

​UE4 remaps the normalized 0 - 1 range to 0 - 0.08 for specular input. This means UE4’s specular component can have a maximum of 8% for its dielectric F0 reflectance value. (F0 is the reflected light intensity at 0° to the view frustum. The “F” component is Fresnel, which describes varying reflected light strength based on viewing angle.) The formulas below calculate the dielectric F0 reflectance value from IOR, followed by applying a conversion for UE4 specular reflectivity use.
DIELECTRIC F0 REFLECTANCE VALUE FORMULA​
​( (1 - IOR) / (1 + IOR) )² = Dielectric F0 Reflectance Value
(D
ielectric F0 Reflectance Value / 0.08) = UE4 Specular Reflectivity Value
MATERIAL
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
NORMALIZED VALUES
Ice
​​sRGB = 818181​
Linear RGB = 
383838
​​sRGB = ​129
Linear RGB = 57
​​sRGB = ​0.506
​Linear RGB = 
0.224​
Water
sRGB = ​898989
​Linear RGB = 
404040​
​​sRGB = ​137
​Linear RGB = 65
​​sRGB = ​0.537
​Linear RGB = 
0.255​
Milk
​​sRGB = ​​8f8f8f
​Linear RGB = 
464646​
​​sRGB = ​143
​Linear RGB = 71
​​sRGB = ​0.561
​Linear RGB = 
0.277​
Skin
​​sRGB = ​​9e9e9e​
​Linear RGB = 575757​
​​sRGB = ​158
​Linear RGB = 89
​​sRGB = ​0.62
​Linear RGB = 
0.35​
Glass
​​sRGB = ​​bababa
​Linear RGB = 7d7d7d

​​sRGB = ​186
​Linear RGB = 128
​​sRGB = ​0.73
​Linear RGB = 
0.5​
Plastic
​​sRGB = ​​bababa
​Linear RGB = 7d7d7d

​​sRGB = ​186
​Linear RGB = 128
​​sRGB = ​0.73
​Linear RGB = 
0.5​
Quartz
​◼
​​sRGB = ​c5c5c5​
​Linear RGB = 8e8e8e​
​​sRGB = ​197
​Linear RGB = 145
​​sRGB = ​0.773
​Linear RGB = 
0.57​
The images below display increasing specular properties.

 Index of Refraction gUIDE

Index of Refraction, or IOR, describes how much light bends through medium to another. The values below are based on real-world, optical measurements.
MATERIAL
INDEX OF REFRACTION
Air
Linear Value = 1​
Ice
Linear Value = 1.31​
Water
​​Linear Value = 1.33​
Common Dielectrics
​​Linear Value = 1.5​
Glass
​​Linear Value = 1.52​
Diamond
Linear Value = 2.42
The images below display increasing index of refraction properties.

CLEAR COAT GUIDE
Clear Coat simulates multilayered materials with dual normal/roughness parameters for a transparent film layer effect on top of dielectric/metallic surfaces. Examples of this kind of material include lacquer, films over car paint/soda cans, and carbon fiber. To use it in UE4, it first needs to be enabled within the Project Settings, followed by changing a material’s Shading Model to Clear Coat. The chart below covers some Clear Coat material properties.
ATTRIBUTE
DESCRIPTION
Clear Coat
​Clear Coat layer strength. This should usually be set to 0 or 1. (black or white for a texture map)
​Clear Coat Roughness
Clear Coat layer roughness attribute.
Normal
Clear Coat layer normal attribute.
​Roughness
​Bottom layer roughness attribute.
ClearCoatBottomNormal
Bottom layer normal attribute. This node needs to be added, with a normal map connected to it, for dual-normal/multidirectional direct light interaction
The images below display increasing Clear Coat properties.

GRAYS GUIDE

GRAY
DESCRIPTION
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
NORMALIZED VALUES
Neutral Gray
Neutral gray can be  used for texturing. 
​sRGB = bababa​
​Linear RGB = 7d7d7d
​sRGB = 186
​Linear RGB = 128
​sRGB = 0.73
​Linear RGB = 0.5

Middle Gray 
18%-gray can be used for lighting tests.
sRGB = 757575​
​Linear RGB = 2d2d2d
​sRGB = 117
​Linear RGB = 46
sRGB = 0.46
​Linear RGB = 0.18 

Gamma Conversion GUIDE

GAMMA CONVERSION
FORMULAS
Gamma Correction-to-Linear RGB
( Gamma Correction Value ^ (1 / 2.2) ) = Linear RGB Value
Linear RGB-to-Gamma Correction
(Linear RGB Value ^ 2.2) = Gamma Correction Value
Normalized Gamma Correction-to-Normalized Linear RGB
(Normalized Gamma Correction Value ^ 2.2) = Normalized Linear RGB Value
(Normalized Linear RGB Value * 255) = Linear RGB Channel Value​
Normalized Linear RGB-to-Normalized Gamma Correction
( Normalized Linear RGB Value ^ (1 / 2.2) ) = Normalized Gamma Correction Value
(Normalized Gamma Correction Value * 255) = Gamma Correction Channel Value

 Dielectric ALBEDO VALUES GUIDE

MATERIAL
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
Forged Iron
sRGB = ​3a383b
​Linear RGB = ​
0a0a0b
sRGB = ​​​(58, 56, 59)
​Linear RGB = ​(10, 9, 10)

Dark Soil
sRGB = ​​553d31​
​Linear RGB = 
170b07
sRGB = ​​​(85, 61, 49)
​Linear RGB = ​(23, 11, 7)

Worn Asphalt
sRGB = ​​5b5b5b​
​Linear RGB = ​
1a1a1a
sRGB = ​​​(91, 91, 91)
​Linear RGB = ​(26, 26, 26)

Varnished Wood
sRGB = ​​875c3c​
​Linear RGB = ​
3e1b0b
sRGB = ​​(135, 92, 60)
Linear RGB = ​(63, 27, 11)
Tree Bark
sRGB = ​​72675b​
​Linear RGB = ​
2b221a
sRGB = ​​(114, 103, 91)
​Linear RGB = ​(43, 35, 26)

Green Vegetation
sRGB = ​​7b824e
​Linear RGB = ​
323913​
sRGB = ​​​(123, 130, 78)
​Linear RGB = ​(51, 58, 19)

Gray Plaster
sRGB = ​​818181​
​Linear RGB = ​
383838​
sRGB = ​​​(129, 129, 129)
​Linear RGB = ​(57, 57, 57)

Brick
sRGB = ​​947d75​
​Linear RGB = ​
4b342d
sRGB = (148, 125, 117)
​Linear RGB = ​(77, 53, 46)

Old Concrete
sRGB = ​​878883​
​Linear RGB = ​
3e3f3a
sRGB = ​​(135, 136, 131)
​Linear RGB = ​(63, 64, 59)

Gray Paint
sRGB = ​​a3a3a3​
​Linear RGB = ​
5d5d5d
sRGB = ​​(163, 163, 163)
Linear RGB = ​(95, 95, 95)
Sand
sRGB = ​​b1a784​
​Linear RGB = ​
70623b
sRGB = ​​​(177, 167, 132)
​Linear RGB = ​(114, 100, 60)

Clean Cement
sRGB = ​​c0bfbb​
​Linear RGB = ​
86857f
sRGB = ​​(192, 191, 187)
Linear RGB = ​(137, 135, 129)
Rough Wood
sRGB = ​​e0c7a8​
​Linear RGB = ​be
9264
sRGB = ​​​(224, 199, 168)
​Linear RGB = ​(192, 148, 102)

Metallic Albedo Values GUIDE

MATERIAL
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
Gold
sRGB = ​ffe29b​
​Linear RGB = ​​ffc253
sRGB = ​​(255, 226, 155)
​Linear RGB = ​​
(255, 196, 85)
Iron
sRGB = ​c4c7c7
​Linear RGB = ​8d9292
sRGB = ​​​​(196, 199, 199)
​Linear RGB = ​​
(143, 148, 148)
Copper
sRGB = ​fad0c0​
​Linear RGB = ​f4a186
sRGB = ​​​​(250, 208, 192)
​Linear RGB = ​​
(244, 163, 137)​
Silver
sRGB = ​fcfaf5​
​Linear RGB = ​f9f4e9
sRGB = ​​​​(252, 250, 245)
​Linear RGB = ​​
(248, 244, 234)
Cobalt
sRGB = ​d3d2cf​
​Linear RGB = ​a6a49f
sRGB = ​​​​(211, 210, 207)
​Linear RGB = ​​
(168, 166, 161)​
Aluminum
sRGB = ​f5f6f6​
​Linear RGB = ​e9ebeb
sRGB = ​​​​(245, 246, 246)
​Linear RGB = ​​
(234, 236, 236)
Titanium
sRGB = ​c1bab1​
​Linear RGB = ​887d70
sRGB = ​​​​(193, 186, 177)
​Linear RGB = ​​
(138, 127, 114)​
Chromium
sRGB = ​c2c3c3​
​Linear RGB = ​8a8b8b​
sRGB = ​​​​(194, 195, 195)
​Linear RGB = ​​
(140, 142, 141)
​Platinum
sRGB = ​d5d0c8​
​Linear RGB = ​aaa193
sRGB = ​​​​(213, 208, 200)
​Linear RGB = ​​
(172, 163, 149)​
Nickel
sRGB = ​d3cbbe​
​Linear RGB = ​a69883
sRGB = ​​​​(211, 203, 190)
​Linear RGB = ​​
(168, 154, 133)

ALBEDO ​​LUMINANCE GUIDE
LUMINANCE FORMULA (Y CHANNEL) 
( (0.3 * Normalized R Channel) + (0.59 * Normalized G Channel) + (0.11 * Normalized B Channel) ) = Normalized Luminance Value
​(Normalized Luminance Value * 255) = Luminance Channel Value
MATERIAL
COLOR SWATCH
HEXADECIMAL VALUES
RGB CHANNEL VALUES
NORMALIZED VALUES
​Silver
sRGB = fafafa​
Linear RGB = ​​f4f4f4
sRGB = ​​​250
Linear RGB = ​​​244
sRGB = ​​​0.98
Linear RGB = ​0.957
​Aluminum
sRGB = ​​f6f6f6
Linear RGB = ​​ebebeb
sRGB = ​​​246
Linear RGB = ​​​235
sRGB = ​​​0.965
Linear RGB = 0.​​922
​Gold
sRGB = ​​e6e6e6
Linear RGB = ​​cacaca
sRGB = ​​​230​
Linear RGB = ​​202
sRGB = ​​​0.902
Linear RGB = ​​0.792
​Copper
sRGB = ​​d9d9d9
Linear RGB = ​​b1b1b1
sRGB = ​​​217​
Linear RGB = ​​177
sRGB = ​​​0.851
Linear RGB = ​​0.694
​Cobalt
sRGB = ​​d2d2d2
Linear RGB = ​​a4a4a4
sRGB = ​​​210​
Linear RGB = ​​164
sRGB = ​​​0.824
Linear RGB = ​​0.643
​Platinum
sRGB = ​​d0d0d0
Linear RGB = ​​a1a1a1
sRGB = ​​​208​
Linear RGB = ​​161
sRGB = ​​​0.816
Linear RGB = ​​0.631
​Nickel
sRGB = ​​cccccc
Linear RGB = ​​9a9a9a
sRGB = ​​​204​
Linear RGB = ​​154
sRGB = ​​​0.8
Linear RGB = ​​0.604
​Rough Wood
sRGB = ​​cbcbcb
Linear RGB = ​​989898​
sRGB = ​​​203​
Linear RGB = ​​152
sRGB = ​​​0.796
Linear RGB = 0.​​596
​Iron
sRGB = ​​c6c6c6
Linear RGB = ​​909090​
sRGB = ​​​198​
Linear RGB = ​​144
sRGB = ​​​0.776
Linear RGB = ​​0.565
Chromium
sRGB = ​​c3c3c3
Linear RGB = ​​8b8b8b
sRGB = ​​​195​
Linear RGB = ​​139
sRGB = ​​​0.765
Linear RGB = ​​0.545
​Clean Cement
sRGB = ​​bfbfbf
Linear RGB = ​​858585​
sRGB = ​​​191​
Linear RGB = ​​133
sRGB = ​​​0.749
Linear RGB = ​​0.522
​Titanium
sRGB = ​​bbbbbb
Linear RGB = ​​7f7f7f
sRGB = ​​​187​
Linear RGB = ​​127
sRGB = ​​​0.733
Linear RGB = ​​0.498
​Sand
sRGB = ​​a7a7a7
Linear RGB = ​​626262​
sRGB = ​​​167​
Linear RGB = ​​98
sRGB = ​​​0.655
Linear RGB = ​​0.384
​Gray Paint
sRGB = ​​a3a3a3
Linear RGB = 5d5d5d​​
sRGB = ​​​163​
Linear RGB = ​​93
sRGB = ​​​0.639
Linear RGB = ​​0.365
​Old Concrete
sRGB = ​​878787
Linear RGB = ​​3e3e3e
sRGB = ​​​135​
Linear RGB = ​​62
sRGB = ​​​0.529
Linear RGB = ​​0.243
​Brick
sRGB = ​​828282
Linear RGB = ​​393939​
sRGB = ​​​130​
Linear RGB = ​​57
sRGB = ​​​0.51
Linear RGB = ​​0.224
​Gray Plaster
sRGB = ​​818181
Linear RGB = ​​383838​
sRGB = ​​​129​
Linear RGB = ​​56
sRGB = ​​​0.506
Linear RGB = ​​0.22
​Green Vegetation
sRGB = ​​7e7e7e
Linear RGB = ​​353535​
sRGB = ​​​126​
Linear RGB = ​​
sRGB = ​​​0.494
Linear RGB = ​​0.208
​Tree Bark
sRGB = 686868​​
Linear RGB = ​​232323​
sRGB = ​​​104​
Linear RGB = ​​35
sRGB = ​​​0.408
Linear RGB = ​​0.137
​Varnished Wood
sRGB = ​​666666
Linear RGB = 222222​​​
sRGB = ​​​102​
Linear RGB = ​​34
sRGB = ​​​0.4
Linear RGB = ​​0.133
​Worn Asphalt
sRGB = ​​5a5a5a
Linear RGB = ​​1a1a1a
sRGB = ​​​90​
Linear RGB = ​​26
sRGB = ​​​0.353
Linear RGB = ​​0.102
​Dark Soil
sRGB = ​​424242
Linear RGB = ​​0d0d0d
sRGB = ​​​66​
Linear RGB = ​​13
sRGB = ​​​0.259
Linear RGB = ​​0.051
Forged Iron
sRGB = ​383838
Linear RGB = 0a0a0a​​
sRGB = ​​​56​
Linear RGB = ​​10
sRGB = ​​​0.22
Linear RGB = ​​0.039

ALBEDO ​​SATURATION % GUIDE
SATURATION FORMULA​
( ((Max(RGB Channel Value) - Min(RGB Channel Value)) / Max(RGB Channel Value)) * 100 ) = Saturation %
MATERIAL
COLOR SWATCH
SATURATION PERCENT
​​Varnished Wood
sRGB = 56%
​Linear RGB = 82%
​​Dark Soil
sRGB = 42%
​Linear RGB = ​​70%
​Green Vegetation
sRGB = 40%
​Linear RGB = ​67%
Gold
sRGB = 39%
​Linear RGB = ​67%
Sand
sRGB = 25%
​Linear RGB = ​​47%
Rough Wood
sRGB = 25%
​Linear RGB = ​​​47%
Copper
sRGB = 23%
​Linear RGB = ​​​45%
Brick
sRGB = 21%
​Linear RGB = ​​40%
​​Tree Bark
sRGB = 20%
​Linear RGB = ​​40%
​​Nickel
sRGB = 10%
​Linear RGB = ​21%
​​Titanium
sRGB = 8%
​Linear RGB = ​​18%
Platinum
sRGB = 6%
​Linear RGB = ​​14%
​Forged Iron
sRGB = 5%
​Linear RGB = ​​9%
​Old Concrete
sRGB = 4%
​Linear RGB = ​​8%
​​Silver
sRGB = 3%
​Linear RGB = ​​6%
​​Clean Cement
​sRGB = 3%
​Linear RGB = ​​5%
Cobalt
sRGB = 2%
​Linear RGB = ​​4%
Iron
sRGB = 2%
​Linear RGB = ​​3%
Chromium
sRGB = 1%
​Linear RGB = ​​1%
Aluminum
sRGB = 1%
​Linear RGB = ​​1%
​Worn Asphalt
sRGB = 0%
​Linear RGB = ​​0%
​​Gray Plaster
sRGB = 0%
​Linear RGB = ​​0%
​​Gray Paint
sRGB = 0%
​Linear RGB = ​​0%