Parameter Reference - Material

Below is an explanation of all the parameters available when editing Material Instances

Not all of the parameters shown below are available for every type of Decal. If a particular parameter is not visible it is because it is unavailable for that Decal blend type or usage. For example Decals which write to the Normal channel cannot use World UV's. This is unfortunately an engine limitation

UV Mapping

UV Tile Adjust global UV Tiling

Use Triplanar Projection Enable Triplanar UV projection (unavailable when using Normal Texture). See example

Triplanar Blend Hardness Adjust how hard or soft the blend is between triplanar angles

Use EdgeMask Texture Enable optional separate EdgeMask to fix Decal volume hard outer edge. Read more about optional separate EdgeMask

Use World Aligned Projection Enable World Aligned UV projection (unavailable when using Normal Texture). See example

Use Spherical Projection Enable Spherical UV projection. See example

Base Color

Brightness Adjust BaseColor brightness value

Colorize Colorize BaseColor

Normal

Intensity Adjust Normal intensity

Roughness

Roughness Multiply Adjust Roughness Value

Metallic

UseTexture Enable use of a Metallic Texture mask

Metallic Add Add a value to Metallic Texture (value used unmodified if no Metallic Texture is enabled)

Opacity

Opacity Multiply Adjust Opacity Value

Angle Fade Enable Angle based fade of Decal Opacity. Fix for projection stretching. See example

Angle Fade Multiplier Adjust Angle Fade amount

Angle Fade Exponent Adjust Angle fade falloff exponent

BackfaceProjectionCull Disable projection on angles greater than 90 degrees from Decal projection. See example

Angle Fade Large World Fix Enable Angle based fade of Decal Opacity. Fix for projection stretching

Depth Fade Enable Depth Fade in World Units along direction of Decal projection. Fix for projection stretching. See example

Depth Fade Distance (units) How far in units it takes for the decal to fade from fully opaque to transparent

Depth Fade Exponent Control Depth fade falloff exponent

Depth Offset (units) Offset in units the point along the Decal projection where the Depth Fade begins

Depth Direction Reverse Reverse the direction which the Depth Fade gradient falls off

Sphere Mask Enable Sphere Opacity Mask based on the position of the Decal Actor. See example

Sphere Radius Radius of the sphere mask in units

Sphere Hardness Control the hardness of the sphere mask gradient

Emissive

Enable Emissive Enable the use of Emissive

Emis Color Colorize Emissive

Emis Brightness Adjust Emissive brightness

Emis Power Adjust Emissive power exponent

Use Texture Mask (Opacity) Enable the use of a Texture to mask Emissive

Mask Influence Adjust the influence of the Texture when masking Emissive

Invert Texture Mask Invert the Texture being used to mask Emissive

BaseColor Affects Emissive Enable BaseColor Texture affect the Emissive color

BaseColor Influence Adjust how much the BaseColor Texture affects Emissive

Use Temperature Enable the use of Black Body temperature/intensity values (Kelvin)

Temperature (K) Temperature value input (Kelvin)

Use Fresnel Enable use of Fresnel falloff Mask

Use Normal Texture Fresnel Enable the use of the Normal Texture when calculating Fresnel falloff. Uses pixel world normal otherwise

Fresnel Exponent Adjust the Fresnel falloff exponent

Parallax Occlusion Mapping (POM)

Use POM Enables the use of Parallax Occlusion Mapping (POM) to simulate depth. Requires Height Texture. See how to enable Height Texture output

Height Ratio This is how 'deep' the heightmap is in relation to its width. Typical values are between 0.05 and 0.1. You can also affect the heightmap depth with Height Range in the graph

Min Steps The Min steps is how many steps will be used when looking downward at the material. Typically fewer steps are required when looking down since there is less resulting offset.

Max Steps The Max Steps is how many steps will be performed at glancing angles where more steps are typically necessary.

Reference Plane The relative point from which the parallax will be applied. When 1 or higher, all parallax will be downwards. When 0, all parallax will be upwards. Defaults to 0.5 - the mid point in a Height Texture

POM Debug Complexity Output min and max steps to Emissive to debug POM complexity

Max Expensive Steps Debug Color Set the Max Steps for POM complexity

Parallax Occlusion Mapping uses Ray Tracing to find the correct offsets at each point. Keep in mind that the material cost will not be easily trackable using the instruction count or shader complexity view due to the nature of the loops involved. Use the debug emissive colors to get an idea of expense based on your specified Min and Max Step sizes. POM currently only works on upward facing surfaces due to the limitations of the Decal Actor projection.