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In this page, you'll find the available Vector Expressions that output vector values mapped to RGBA. These can be used for a myriad of different effects for creating your Materials for things like getting an object's position in world space so that the Material can react or transitioning colors on a character when they enter a specific area. There are many others that enable you to control spacial local style material effects that you can look the examples below learn more about.

ActorPositionWS

ActorPositionWS outputs Vector3 (RGB) data representing the location of the object with this material on it in world-space.

In this example, you can see that ActorPositionWS is being fed directly into the Base Color of the material. As a result, each of the spheres with the material applied to them show a different color as they are moved to different locations in 3D space. Note that the result of the ActorPositionWS node is being divided by 1600 to create a nice blend-in color, rather than a pop.

CameraPositionWS

The CameraWorldPosition expression outputs a three-channel vector value representing the camera's position in world space.

The preview sphere changes color as the camera rotates.

CameraVectorWS

The CameraVector expression outputs a three-channel vector value representing the direction of the camera with respect to the surface, in other words, the direction from the pixel to the camera.

Example Usage: CameraVector is often used to fake environment maps by connecting the CameraVector to a ComponentMask and use the x and y channels of the CameraVector as texture coordinates.

LightVector

Object Bounds

The Object Bounds expression outputs the size of the object in each axis. If used as color, the X, Y, and Z axes correspond to R, G, and B, respectively.

In the example above, you can see that the colors of the objects correspond to the longest axis of the object.

ObjectOrientation

The ObjectOrientation expression outputs the world-space up vector of the object. In other words, the object's local positive z-axis is pointing in this direction.

ObjectPositionWS

The ObjectPositionWS expression outputs the world-space center position of the object's bounds. For example, this is useful for creating spherical lighting for foliage.

PixelNormalWS

The PixelNormalWS expression outputs vector data representing the direction that pixels are facing based on the current normal.

In this example, PixelNormalWS is fed into Base Color. Notice how the normal map is used to give the per-pixel result.

Pre-Skinned Local Normal

The Pre-Skinned Local Normals Vector Expression outputs a three-channel vector value representing the local surface normal for Skeletal and Static Meshes. This enables you to achieve locally-aligned tri-planar materials and mesh aligned effects in your materials.

In this example, the material is using a tri-planar texture aligned to the mesh's local surface normal.

Pre-Skinned Local Position

The Pre-Skinned Local Position Vector Expression outputs a three-channel vector value that gives access to a Skeletal Mesh's default pose position data for use in per-vertex outputs. This enables you to have localized effects on an animated character. This vector expression can also be used with Static Meshes, which will return the standard local position.

In this example, the Skeletal Mesh's default pose is used for mapping versus the default UV mapping on the right.

ReflectionVectorWS

The ReflectionVectorWS expression is similar in spirit to CameraVectorWS , but it outputs a three-channel vector value representing the camera direction reflected across the surface normal.

Example Usage: ReflectionVector is commonly used in environment maps, where the x/y components of the reflection vector are used as UVs into a cubemap texture.

VertexNormalWS

The VertexNormalWS expression outputs the world-space vertex normal. It can only be used in material inputs that are executed in the vertex shader, like WorldPositionOffset. This is useful for making a mesh grow or shrink. Note that offsetting position along the normal will cause the geometry to split apart along UV seams.

In the example above, the preview sphere would seem to scale up and down with sinusoidal motion, as each of the vertices moved in their own normal directions.

Vector Noise

The Vector Noise Material expression adds several more 3D or 4D vector noise results to use in your Materials. Due to the run-time expense of these functions, it is recommended that once a look is developed with them, all or part of the computation be baked into a Texture using the Draw Material to Render Target Blueprint feature introduced in Unreal Engine 4.13 and later. These Material graph Expressions allow procedural looks to be developed in the engine on final assets, providing an alternative to creating procedurally generated Textures with an external tool to apply to assets in UE4. Inside of the Vector Noise Material Expression, you will find the following Vector Noise types.

Below is a simple stone bed material using the distance component of the Vector Noise / Voronoi to modulate some surface bumps and blend in moss in the cracks, and the seed position together with Vector Noise / Cellnoise to change the color and bump height per rock.

The derivative-based operations Perlin Curl and Perlin Gradient can be added together in octaves, just as regular Perlin noise can. For derivatives of more complex expressions, it is necessary to compute the gradient of the result of the expression. To help with this, place the expression to compute into a Material Function and use it with the following helper nodes.

Below you will find descriptions of the various noise functions you will find in the Vector Noise Material Expression.

• Cell Noise Material Example:

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• Perlin Gradient Material Example:

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• Voronoi Material Example:

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