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PBR GUIDE LINKS
UE4 CUSTOM VIEW MODES (made in UE 4.19)
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 heatmaps, Rec.709 broadcast legal levels, AO coloring, 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 (made 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.
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. |
Lux |
Reflected surface illuminance. Also, 1 lux = 1 lm/m². |
Cd/m² (cd = candela) |
Light source intensity per square meter. |
Nit |
= cd/m². |
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. |
LIGHT VALUES GUIDE
DESCRIPTION |
LUX, NIT, or CD/M² VALUES |
Brightest Sunlight |
120,000 |
Sunlight Range |
30,000 - 120,000 |
Bright Sunlight |
111,000 |
White Paper at Sunny Noon |
25,000 |
Clear, Midday Shade |
20,000 |
Fluorescent Lights |
12,000 |
Brightest, White Clouds |
10,000 |
Average, Clear Sky |
5,000 - 7,000 |
Midday Overcast |
1,000 - 2,000 |
HDR10 LCD Monitor |
1,000 |
Clear Sunrise/Sunset |
400 |
LCD Monitor |
250 |
Thickest, Midday Storm Clouds |
< 200 |
Sunrise/Sunset Overcast |
40 |
Floodlit Buildings |
2 |
Thickest Sunrise/Sunset Storm Clouds |
< 1 |
Clear Night with Full Moon |
0.25 |
Clear Night with Quarter Moon |
0.01 |
Clear, Moonless Night with Airglow |
0.002 |
Clear, Moonless Night |
0.0002 |
Moonless Night Overcast |
0.0001 |
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.
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: The Matted, White Paper Test | UE4 Cubemap Orientation 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.
• 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. 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.
• Sky: Uses cd/m², or nit, values. 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.)
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. You can apply Light Values Guide and Color Temperature Guide data to lights' Intensity/Temperature parameters.
• Atmospheric Fog approximates light scattering effects in the atmosphere. This feature can be used by adding an Exponential Height Fog to your scene and enabling its Volumetric Fog option. You can only have one active fog actor at a time. Also, 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 the 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.
• An alternative way to set/measure the sky's average luminance in cd/m², or nits, is by sampling 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.
Note: Sky 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 property terms/definitions.
TERM |
DEFINITION |
Aperture |
Controls the amount of light that enters the camera via its opening size, as well as depth of field. |
Shutter Speed |
The 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.
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.
TERM |
DEFINITION |
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 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.
• 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.
THE MATTED, WHITE PAPER TEST (made 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 Guide | Edge Padding Guide
Note: This guide assumes the reader has a basic understanding of PBR.
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 |
DEFINITION |
# 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 Guide | Grays Guide | Gamma Conversion Guide | Dielectric Albedo Values Guide | Metallic Albedo Values Guide | Albedo Luminance Guide | Albedo Saturation % 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.
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. |
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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.
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.
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 Dielectric F0 Reflectance Value / 0.08 = UE4 Specular Reflectivity Value |
MATERIAL |
COLOR SWATCH |
HEXADECIMAL VALUES |
RGB CHANNEL VALUES |
NORMALIZED VALUES |
Ice |
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sRGB = 818181 Linear RGB = 383838 |
sRGB = 129 Linear RGB = 57 |
sRGB = 0.506 Linear RGB = 0.224 |
Water |
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sRGB = 898989 Linear RGB = 404040 |
sRGB = 137 Linear RGB = 65 |
sRGB = 0.537 Linear RGB = 0.255 |
Milk |
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sRGB = 8f8f8f Linear RGB = 464646 |
sRGB = 143 Linear RGB = 71 |
sRGB = 0.561 Linear RGB = 0.277 |
Skin |
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sRGB = 9e9e9e Linear RGB = 575757 |
sRGB = 158 Linear RGB = 89 |
sRGB = 0.62 Linear RGB = 0.35 |
Glass |
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sRGB = bababa Linear RGB = 7d7d7d |
sRGB = 186 Linear RGB = 128 |
sRGB = 0.73 Linear RGB = 0.5 |
Plastic |
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sRGB = bababa Linear RGB = 7d7d7d |
sRGB = 186 Linear RGB = 128 |
sRGB = 0.73 Linear RGB = 0.5 |
Quartz |
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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. |
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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. |
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sRGB = 757575 Linear RGB = 2d2d2d |
sRGB = 117 Linear RGB = 46 |
sRGB = 0.46 Linear RGB = 0.18 |
Gamma Conversion GUIDE
GAMMA CONVERSION |
FORMULA |
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 |
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sRGB = 3a383b Linear RGB = 0a0a0b |
sRGB = (58, 56, 59) Linear RGB = (10, 9, 10) |
Dark Soil |
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sRGB = 553d31 Linear RGB = 170b07 |
sRGB = (85, 61, 49) Linear RGB = (23, 11, 7) |
Worn Asphalt |
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sRGB = 5b5b5b Linear RGB = 1a1a1a |
sRGB = (91, 91, 91) Linear RGB = (26, 26, 26) |
Varnished Wood |
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sRGB = 875c3c Linear RGB = 3e1b0b |
sRGB = (135, 92, 60) Linear RGB = (63, 27, 11) |
Tree Bark |
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sRGB = 72675b Linear RGB = 2b221a |
sRGB = (114, 103, 91) Linear RGB = (43, 35, 26) |
Green Vegetation |
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sRGB = 7b824e Linear RGB = 323913 |
sRGB = (123, 130, 78) Linear RGB = (51, 58, 19) |
Gray Plaster |
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sRGB = 818181 Linear RGB = 383838 |
sRGB = (129, 129, 129) Linear RGB = (57, 57, 57) |
Brick |
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sRGB = 947d75 Linear RGB = 4b342d |
sRGB = (148, 125, 117) Linear RGB = (77, 53, 46) |
Old Concrete |
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sRGB = 878883 Linear RGB = 3e3f3a |
sRGB = (135, 136, 131) Linear RGB = (63, 64, 59) |
Gray Paint |
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sRGB = a3a3a3 Linear RGB = 5d5d5d |
sRGB = (163, 163, 163) Linear RGB = (95, 95, 95) |
Sand |
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sRGB = b1a784 Linear RGB = 70623b |
sRGB = (177, 167, 132) Linear RGB = (114, 100, 60) |
Clean Cement |
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sRGB = c0bfbb Linear RGB = 86857f |
sRGB = (192, 191, 187) Linear RGB = (137, 135, 129) |
Rough Wood |
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sRGB = e0c7a8 Linear RGB = be9264 |
sRGB = (224, 199, 168) Linear RGB = (192, 148, 102) |
Metallic Albedo Values GUIDE
MATERIAL |
COLOR SWATCH |
HEXADECIMAL VALUES |
RGB CHANNEL VALUES |
Gold |
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sRGB = ffe29b Linear RGB = ffc253 |
sRGB = (255, 226, 155) Linear RGB = (255, 196, 85) |
Iron |
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sRGB = c4c7c7 Linear RGB = 8d9292 |
sRGB = (196, 199, 199) Linear RGB = (143, 148, 148) |
Copper |
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sRGB = fad0c0 Linear RGB = f4a186 |
sRGB = (250, 208, 192) Linear RGB = (244, 163, 137) |
Silver |
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sRGB = fcfaf5 Linear RGB = f9f4e9 |
sRGB = (252, 250, 245) Linear RGB = (248, 244, 234) |
Cobalt |
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sRGB = d3d2cf Linear RGB = a6a49f |
sRGB = (211, 210, 207) Linear RGB = (168, 166, 161) |
Aluminum |
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sRGB = f5f6f6 Linear RGB = e9ebeb |
sRGB = (245, 246, 246) Linear RGB = (234, 236, 236) |
Titanium |
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sRGB = c1bab1 Linear RGB = 887d70 |
sRGB = (193, 186, 177) Linear RGB = (138, 127, 114) |
Chromium |
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sRGB = c2c3c3 Linear RGB = 8a8b8b |
sRGB = (194, 195, 195) Linear RGB = (140, 142, 141) |
Platinum |
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sRGB = d5d0c8 Linear RGB = aaa193 |
sRGB = (213, 208, 200) Linear RGB = (172, 163, 149) |
Nickel |
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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 |
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sRGB = fafafa Linear RGB = f4f4f4 |
sRGB = 250 Linear RGB = 244 |
sRGB = 0.98 Linear RGB = 0.957 |
Aluminum |
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sRGB = f6f6f6 Linear RGB = ebebeb |
sRGB = 246 Linear RGB = 235 |
sRGB = 0.965 Linear RGB = 0.922 |
Gold |
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sRGB = e6e6e6 Linear RGB = cacaca |
sRGB = 230 Linear RGB = 202 |
sRGB = 0.902 Linear RGB = 0.792 |
Copper |
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sRGB = d9d9d9 Linear RGB = b1b1b1 |
sRGB = 217 Linear RGB = 177 |
sRGB = 0.851 Linear RGB = 0.694 |
Cobalt |
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sRGB = d2d2d2 Linear RGB = a4a4a4 |
sRGB = 210 Linear RGB = 164 |
sRGB = 0.824 Linear RGB = 0.643 |
Platinum |
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sRGB = d0d0d0 Linear RGB = a1a1a1 |
sRGB = 208 Linear RGB = 161 |
sRGB = 0.816 Linear RGB = 0.631 |
Nickel |
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sRGB = cccccc Linear RGB = 9a9a9a |
sRGB = 204 Linear RGB = 154 |
sRGB = 0.8 Linear RGB = 0.604 |
Rough Wood |
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sRGB = cbcbcb Linear RGB = 989898 |
sRGB = 203 Linear RGB = 152 |
sRGB = 0.796 Linear RGB = 0.596 |
Iron |
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sRGB = c6c6c6 Linear RGB = 909090 |
sRGB = 198 Linear RGB = 144 |
sRGB = 0.776 Linear RGB = 0.565 |
Chromium |
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sRGB = c3c3c3 Linear RGB = 8b8b8b |
sRGB = 195 Linear RGB = 139 |
sRGB = 0.765 Linear RGB = 0.545 |
Clean Cement |
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sRGB = bfbfbf Linear RGB = 858585 |
sRGB = 191 Linear RGB = 133 |
sRGB = 0.749 Linear RGB = 0.522 |
Titanium |
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sRGB = bbbbbb Linear RGB = 7f7f7f |
sRGB = 187 Linear RGB = 127 |
sRGB = 0.733 Linear RGB = 0.498 |
Sand |
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sRGB = a7a7a7 Linear RGB = 626262 |
sRGB = 167 Linear RGB = 98 |
sRGB = 0.655 Linear RGB = 0.384 |
Gray Paint |
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sRGB = a3a3a3 Linear RGB = 5d5d5d |
sRGB = 163 Linear RGB = 93 |
sRGB = 0.639 Linear RGB = 0.365 |
Old Concrete |
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sRGB = 878787 Linear RGB = 3e3e3e |
sRGB = 135 Linear RGB = 62 |
sRGB = 0.529 Linear RGB = 0.243 |
Brick |
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sRGB = 828282 Linear RGB = 393939 |
sRGB = 130 Linear RGB = 57 |
sRGB = 0.51 Linear RGB = 0.224 |
Gray Plaster |
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sRGB = 818181 Linear RGB = 383838 |
sRGB = 129 Linear RGB = 56 |
sRGB = 0.506 Linear RGB = 0.22 |
Green Vegetation |
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sRGB = 7e7e7e Linear RGB = 353535 |
sRGB = 126 Linear RGB = |
sRGB = 0.494 Linear RGB = 0.208 |
Tree Bark |
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sRGB = 686868 Linear RGB = 232323 |
sRGB = 104 Linear RGB = 35 |
sRGB = 0.408 Linear RGB = 0.137 |
Varnished Wood |
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sRGB = 666666 Linear RGB = 222222 |
sRGB = 102 Linear RGB = 34 |
sRGB = 0.4 Linear RGB = 0.133 |
Worn Asphalt |
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sRGB = 5a5a5a Linear RGB = 1a1a1a |
sRGB = 90 Linear RGB = 26 |
sRGB = 0.353 Linear RGB = 0.102 |
Dark Soil |
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sRGB = 424242 Linear RGB = 0d0d0d |
sRGB = 66 Linear RGB = 13 |
sRGB = 0.259 Linear RGB = 0.051 |
Forged Iron |
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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 |
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sRGB = 56% Linear RGB = 82% |
Dark Soil |
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sRGB = 42% Linear RGB = 70% |
Green Vegetation |
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sRGB = 40% Linear RGB = 67% |
Gold |
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sRGB = 39% Linear RGB = 67% |
Sand |
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sRGB = 25% Linear RGB = 47% |
Rough Wood |
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sRGB = 25% Linear RGB = 47% |
Copper |
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sRGB = 23% Linear RGB = 45% |
Brick |
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sRGB = 21% Linear RGB = 40% |
Tree Bark |
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sRGB = 20% Linear RGB = 40% |
Nickel |
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sRGB = 10% Linear RGB = 21% |
Titanium |
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sRGB = 8% Linear RGB = 18% |
Platinum |
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sRGB = 6% Linear RGB = 14% |
Forged Iron |
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sRGB = 5% Linear RGB = 9% |
Old Concrete |
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sRGB = 4% Linear RGB = 8% |
Silver |
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sRGB = 3% Linear RGB = 6% |
Clean Cement |
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sRGB = 3% Linear RGB = 5% |
Cobalt |
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sRGB = 2% Linear RGB = 4% |
Iron |
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sRGB = 2% Linear RGB = 3% |
Chromium |
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sRGB = 1% Linear RGB = 1% |
Aluminum |
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sRGB = 1% Linear RGB = 1% |
Worn Asphalt |
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sRGB = 0% Linear RGB = 0% |
Gray Plaster |
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sRGB = 0% Linear RGB = 0% |
Gray Paint |
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sRGB = 0% Linear RGB = 0% |