UE4 WorldPositionOffset

WorldPositionOffset

Material
Function Reference

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WorldPositionOffset
Functions

SimpleGrassWind
SplineThicken
CameraOffset
ObjectPivotPoint
ObjectScale
PivotAxis
RotateAboutWorldAxis_cheap
StaticMeshMorphTargets
Wind

The WorldPositionOffset category contains special functions for applying manipulating vertices of a mesh via world position offset. These functions can be chained together for additive effects.

WorldPositionOffset Functions

The following is a list of all the functions underneath the WorldPositionOffset category.

SimpleGrassWind

This function applies a basic wind operator to foliage, giving the ability to specify a weight map and wind strength. This is a non-directional wind that just gives a very general movement to foliage. This should be the last WPO node you add.

Item	Description
Inputs
WindIntensity (Scalar)	Controls how much the wind affects the mesh.
WindWeight (Scalar)	This is a grayscale map that controls how much the mesh's vertices will respond to the wind.
AdditionalWPO (Vector3)	Takes in any additional world position offset networks or functions.

SplineThicken

The SplineThicken function serves as a way to make very thin polygons look thicker at render time. This is perfect for cables, hair, grass, and other such objects.

Objects using this function should be extremely thin and should be imported with "Remove Degenerate Triangles" disabled.

Item	Description
Inputs
WidthBase (Scalar)	This sets the width of a single polygon object at its base.
WorldPosition (Vector3)	World Position takes in any existing world position offset functions and adds this function to them.
WidthTip (Scalar)	Sets the width of a polygon object at its tip.
TexCoord (Vector2)	Add a texture coordinate to use in the expansion of the spline. This defaults to texture coordinate 0.
Expand U or V UV Channel (StaticBool)	Sets whether to expand the mesh in U or V. Defaults to true, which is U.
Outputs
WorldPositionOffset	This is the output that you can add to other world position offset calculations.
Normal	The outgoing normal of the adjusted geometry.

CameraOffset

The CameraOffset function is great to assist with depth sorting, as it allows you to move an object in camera space, either toward or away from the camera.

Item	Description
Inputs
OffsetAmount (Scalar)	Enter a negative or positive number to offset your model in the direction of the camera. Note that positive values will bring the model closer to the camera and cause rendering errors if the mesh greatly exceeds the models bounding box.
ObjectCenter (Vector3)	Enter the model's center point to be used in the creation the offset vector. Default Value = Object World Position.

ObjectPivotPoint

The ObjectPivotPoint function returns the object's pivot point in world space. This is not compatible with the pixel shader.

Item	Description
Outputs
Object Pivot Location	Returns the object's pivot point in world space. This only works with the vertex shader and is incompatible with the pixel shader.

ObjectScale

The ObjectScale function returns the object's XYZ scale together and seperately. This is not compatible with the pixel shader.

Item	Description
Outputs
Scale XYZ	Returns a float3 value that is equal to the objects XYZ scale. This is not compatible with the pixel shader.
Scale X	Returns a scalar value that is equal to the object's X-scale. This is not compatible with the pixel shader.
Scale Y	Returns a scalar value that is equal to the object's Y-scale. This is not compatible with the pixel shader.
Scale Z	Returns a scalar value that is equal to the object's Z-scale. This is not compatible with the pixel shader.

PivotAxis

The PivotAxis function creates a common pivot location on arbitrary axes. This is helpful for creating flag motion. Instead of using a single pivot point near the top of the flag, use a shared Z point and unique X and Y location data to create a more realistic
connection along the object's width.

This shader node only supports uniform scaling. Also, the rotate about axis axis and the pivot axis/pos should not coincide.

Item	Description
Inputs
Pivot Axis/Pos (Vector3)	Enter a number to use as both your local axis line axis and position. If you would like to lock off your model, enter on its local z axis near its pivot enter (0,0,1). If you would like to lock of the top of the model, enter your model's height in as (0,0,model height).
Outputs
Pivot	This can be used as the pivot point in the rotate about axis node.

RotateAboutWorldAxis_cheap

This function cheaply rotates objects around world axes. Input the angle you would like to use and attach the output to world position offset.

Item	Description
Inputs
Rotation Amount (Scalar)	A value of one is equal to one full rotation.
PivotPoint (Vector3)	World space location of individual vertices. The WorldPosition node is typically used.
WorldPosition (Vector3)	World space location of pivot point to rotate around. The default value is the model's pivot point.
Outputs
X-Axis	Cheaply rotates the object around the world X-axis.
Y-Axis	Cheaply rotates the object around the world Y-axis.
Z-Axis	Cheaply rotates the object around the world Z-axis.

StaticMeshMorphTargets

The StaticMeshMorphTargets function unpacks morph target data that was added into a via 3ds Max's Morph Packer MAXScript.

Item	Description
Outputs
Morph Target 1 Normals	The surface normals that are associated with Morph Target 1.
Morph Target 1 WPO	World position offset for Morph Target 1.
Morph Target 2 WPO	World position offset for Morph Target 2.

Wind

The Wind function provides separate outputs for wind strength, speed multiplied by time and a normalized wind vector.

Item	Description
Inputs
WindActor (Vector4)	This will take in a Wind actor (in development). At this time you may use a Vector4 to designate direction and strength of the wind.
Outputs
Normalized Wind Vector	The wind vector, normalized to 0-1 space.
WindStrength	Returns wind strength. The magnitude of the wind vector found by calculating distance from the wind vector to 0.
WindSpeed	Wind speed multiplied by time.
WindActor	Standard WindActor node.