UE4 – Triplanar projection mapping setup

Software:
Unreal Engine 4.25

Triplanar Projection Mapping can be an effective texture mapping solution for cases where the model doesn’t have naturally flowing continuous UV coordinates, or there is a need to have the texture projected independently of UV channels, with minimally visible stretching and other mapping artifacts.
Classic use cases for Triplanar Projection Mapping are terrains and organic materials. provided that the image being used is a seamless texture, no seams will be visible because this projection type isn’t affected by UV coordinates.
Triplanar Projection Mapping can also be used in world space to create a continuous texture between separate meshes, allowing the meshes to be indestructibly transformed and edited.

How does Triplanar Projection Mapping work?
Triplanar Projection Mapping is a linear blend between 3 orthogonal 2D planar texture projections, typically each aligned to a natural world or object axis.
The more the surface faces an axis, the higher the weight of this axis projection in the final blend.

UE4 local (object) space Triplanar Projection Mapping material setup:
* It’s usually more efficient to create this setup as a Material Function

  1. Local shading coordinates are multiplied by by a “density” parameter to allow convenient scaling of the projected.
  2. The scaled coordinates vector is separated to its components who are combined to 3 pairs of planar coordinates XY, XZ and YZ, and fed as the sample coordinates to the 3 Texture Sample nodes.
  3. The Vertex Normal input vector is transformed to local space, converted to absolute value (absolute orientation in the positive axes octant) and separated to its X, Y and Z components so they can serve as blend weights in the mix.
  4. Each of the 3 planar axis projections is multiplied by the blend factors, and the resulting values are added to the raw mix.
  5. A value of 1.0 is divided by the Normal vector component values to obtain the factor needed to normalize the blend result to a value of 1.0.
  6. The raw blend value is multiplied by the normalizing factor so the blend resulting color will be normalized.
    * The blend weights should add to a value of 1.0, but a unit vector’s values add up to more than 1 in diagonal directions. for this reason, without this final step, the color of the texture in point on the surface that are diagonal to the projection axes will appear brighter than in points on the surface that face a projection axis.

An example of Triplanar Projection Mapping in world space:

A bunch of Blender monkeys (Suzanne) continuously textured using world space Triplanar Projection Mapping:

Related posts:
UE4 – Material Functions
UE4 – Material Instances
UE4 – Bump mapping
UE4 – Procedural bump mapping

UE4 – Procedural 3D noise bump setups

Software:
Unreal Engine 4.25

Yet another case where I develop my own costly solution only to find out afterwards that there’s actually a much more efficient built-in solution.. ūüėÄ

In this case the subject is deriving a bump normal from a procedural or non-uv projected height map/texture (like noise, or tri-planar mapping for example).

The built-in way:
Using the pre-made material functions, PreparePerturbNormalHQ and PerturbNormalHQ, the first of which uses the low level Direct3D functions DDX and DDY to derive the two extra surface adjacent values needed to derive a bump normal, and the last uses the 3 values to generate a world-space bump normal:

240 instructions
  1. Noise coordinates are obtained by multiplying the surface shading point local position by a value to set the pattern density.
  2. The Noise output value is multiplied by a factor to set the resulting bump intensity.
  3. The PreparePerturbNormalHQ function is used to derive the 2 extra values needed to derive a bump normal.
  4. The PerturbNormalHQ function is used to derive the World-Space bump normal.
  5. Note:
    Using this method, the material’s normal input must be set to world-space by unchecking Tangent Space Normal in the material properties.

The method I’m using:
This method is significantly more expensive in the number of shader instructions, but in my opinion, generates a better quality bump.
Sampling 3 Noise nodes at 3 adjacent locations in tangent-space to derive the 3 input values necessary for the NormalFromFunction material function:

412 instructions
  1. Noise coordinates are obtained by multiplying the surface shading point local position by a value to set the pattern density.
  2. Crossing the vertex normal with the vertex tangent vectors to derive the bitangent (sometimes called “binormal”).
  3. Multiplying the vertex-tangent and bitangent vectors by a bump-offset* factor to create the increment steps to the additional sampled Noise values.
    * This factor should be parameter for easy tuning, since it determines the distance between the height samples in tangent space.
  4. The increment vectors are added to the local-position to get the final height samples positions.
  5. The NormalFromFunction material function is used to derive a tangent-space normal from the 3 supplied height samples.

Note:
From my experience, even though the UV1, UV2 and UV3 inputs of the NormalFromFunction are annotated as V3, the function will only work is the inputs are a scalar value and not a vector/color.

Related:
UE4 – Material Functions
UE4 – Bump map
UE4 – fix an inverted normal map
UE4 – Triplanar mapping

UE4 – Quick fix for normal map encoding

Software:
Unreal Engine 4.25 | Photoshop 2020

Quick UE normal map tip:
If you load a normal map into a UE material and the result appears inverted, i.e. holes instead of bumps or the other way:

The quick fix:

  1. In the texture settings, check the Flip Green Channel option and save it:

Annotation 2020-09-06 160838

The deep fix:
* This can be performed an automated action on multiple files

  1. Open the normal map in Photoshop
  2. In the Channels panel, select the Green channel
  3. Press Ctrl + I,
    Or Select Image > Adjustments > Invert
    To invert the green channel.
  4. Save the texture and reload into Unreal Engine.
    Annotation 2020-07-06 233156

Inverted normal map:Annotation 2020-07-06 232554

Fixed normal map:Annotation 2020-07-06 233036

Related:
UE4 Bump map
UE4 – Procedural Bump Normals

UE4 – Technical model visualization tips

Software:
Unreal Engine 4.25

This post is a summary of the tips given by Epic Games technical-artist Min Oh in his GDC 2017 lecture about improving photo-realism in product visualization, more specifically, how to render high quality surfaces.
I recommend watching the full lecture:

  1. Render sharper reflections by increasing the Cubemap resolution of reflection captures:
    Project Settings > Engine > Rendering > Reflection > Reflection Capture Resolution
    * use powers of 2 values i.e. 256, 512, 1024….
    Annotation 2020-07-06 195120
  2. Improve the accuracy of environment lighting by increasing the Cubemap resolution of the Skylight:
    * use powers of 2 values i.e. 256, 512, 1024….
    Annotation 2020-07-06 202415
  3. Improve screen space effects accuracy like screen space reflections by setting the engine to compute high precision normals for the GBuffer:
    Set Project Settings > Engine > Rendering > Optimizations > GBuffer Format to:
    High Precision Normals
    Annotation 2020-07-06 204022
  4. Use a high degree of tessellation (subdivision) for the models pre-import.
    Simpy put:
    Use high quality models.
  5. Improve the surfaces tangent space accuracy, and as a result also the shading/reflection accuracy by setting the model’s static mesh components to encode high precision tangent basis:
    Static Mesh Editor > Details > LOD 0 > Build Settings > Use High Precision Tangent basis
    Annotation 2020-07-06 210030
  6. Creating materials with rich dual specular layers by enabling material clear coat separate normal input:
    Project Settings > Engine > Rendering > Materials > Clear Coat Enable Second Normal
    Annotation 2020-07-06 211152Set the material Shading Model to Clear Coat and use a ClearCoatBottomNormal input node to add a normal map for the underlying layer:
    Annotation 2020-07-06 221027

 

Related:

  1. UE4 – Lighting calculation tips
  2. UE4 HDRI lighting
  3. UE4 РEnable DXR ray-traced reflections 

UE4 – Creating two sided material effects using the TwoSidedSign node

Software:
Unreal Engine 4.24

The TeoSidedSign node let’s the shader “know” if a rendered polygon is facing the camera or not by outputting a value of 1 for facing polys and -1 for back-facing polys.
This is useful for creating materials that have different properties when seen front-facing or back-facing.

Example 1:
Blending two different colors based on face direction:

  1. Check the Two Sided material attribute.
    * Needed so that the engine will render the polygons beck sides.
  2. In the material blueprint, create a blend of to colors using a Lerp (LinearInterpolate) node and connect it to the material’s Base Color input.
  3. Add a TwoSidedSign node to get polygon facing input (1,-1).
  4. Connect the TwoSidedSign node’s output to a Clamp node to clamp the values to (1,0).
  5. Connect the¬† Clamp node’s output to the Lerp node’s Alpha input so that the polygon’s facing direction will control the Lerp blend.

Note:
You can use this method to blend any other material attribute based on polygon facing direction.

Annotation 2020-05-11 133226

 

Example 2:
Create an “inwards facing” flipped normal material:

  1. Set the material’s Blend Mode to Masked.
    * Needed for being able to make areas parts of the mesh invisible.
  2. Check the Two Sided material attribute.
    * Needed so that the engine will render the polygons beck sides.
  3. Add a TwoSidedSign node to get polygon facing input (1,-1).
  4. Connect the TwoSidedSign node’s output to a Clamp node to clamp the values to (1,0).
  5. Connect the Clamp node’s output to a 1-X node to invert the facing input.
  6. Connect the 1-X node’s output to the material’s Opacity Mask input so that polygons facing the camera will be invisible.

Annotation 2020-05-11 130703

 

Related:

  1. Blending material using Paint
  2. Material Functions
  3. UE4 Bump Map

UE4 – Using a Post Process material to create a simple fog effect

Software:
Unreal Engine 4.24

An example of a simple fog effect created using a Post Process material:

 

The fog material Blueprint:
The method for creating the fog effect is to take distance of the objects from the camera, map it to a value range suitable for color blending 0 – 1, and use that for blending the object’s color with the fog color, so the further away the object, the more it will be colored by the fog.
Start by creating a new material, and follow the details below to create the Blueprint:

Fog_PP_material

  1. The Material Domain is set to Post Process.
    And has its Blendable Location parameter set to Before Tonemapping so it will be applied on the raw render.
    Annotation 2020-05-04 011312
  2. A SceneTexture node with its Scene Texture Id parameter set to PostProcessInput0 serves as the input of the view’s original rendered pixel colors:
    Annotation 2020-05-04 011050
  3. A Lerp (LinearInterpolate) node calculates the blending of the view’s original pixel colors with the Fog color to create the fog effect.
  4. A SceneTexture node with its Scene Texture Id parameter set to SceneDepth serves as the input of depth of each pixel (distance from camera):
    Annotation 2020-05-04 012256
  5. A ComponentMask node set to the R channel allows using the depth data as a single float value instead of a Vector4:
    Annotation 2020-05-04 012603
  6. A Clamp node is used to clamp (limit) the depth value to the Fog’s maximum depth value (see below)
  7. A RemapValueRange maps the distance value to a fog density value that will be used as the Lerp (3) alpha parameter.
    Simply put, the further the object, the more the original color will be blended with the fog color.
  8. A Power node (raises the fog blend factor by an exponent) make the fog blending non-linear, that is beginning gently for closer objects and than increasing more drastically as the distance grows (provided that the exponent value is above 1)
  9. A Constant Vector4 serves as an input for the fog color.
    * Note that having this input be a Vector4 and not a Vector3 allows it to be interpolated with the PostProcessInput0 data, otherwise a ComponentMask (RGB) node would have been necessary to convert the PostProcessInput0 to a Vector3.
  10. a float constant serves as an input for the fog’s minimal distance (from camera)
  11. a float constant serves as an input for the fog’s maximal distance (from camera)
    *¬† Note that it’s connected both to the Clamp node and to the¬†RemapValueRange node.
  12. a float constant serves as an input for the fog’s minimal opacity (blend amount)
  13. a float constant serves as an input for the fog’s maximal opacity (blend amount)
  14. a float constant serves as an input for the fog’s blend exponent.

 

Applying the Post Process material to the level:

Fog_2

  1. Select the PostProcessVolume actor in the World Outliner window.
    * Create a PostProcessVolume actor if necessary.
  2. In the Details panel, under Rendering Features > Post Process materials,
    Add a new item to the array, in the new item’s value choose Asset Reference,
    And then select your fog material:
    Annotation 2020-05-04 015354
    Annotation 2020-05-04 015831

 

Related:

  1. Material Functions
  2. Blending materials
  3. Blending materials using texture paint

UE4 Material Blueprint Shortcuts

Software:
Unreal\n Engine 4.24

Some useful Unreal Editor Material Blueprint shortcuts:

  1. Hold 1 and LMB Click to create a 1D Constant node:
    Annotation 2019-12-26 005530
  2. Hold 2 and LMB Click to create a 2D Constant node:
    Annotation 2019-12-26 005549
  3. Hold 3 and LMB Click to create a 3D Constant node:
    Annotation 2019-12-26 005605
  4. Hold S and LMB Click to create a Scalar Parameter node:
    Annotation 2019-12-26 005618
  5. Hold V and LMB Click to create a Vector Parameter node:
    Annotation 2019-12-26 005631
  6. Hold L and LMB Click to create a Lerp (Linear Interpolate) node:Annotation 2019-12-26 005653
  7. Hold M and LMB Click to create a Multiply node:
    Annotation 2019-12-26 005722
  8. Hold A and LMB Click to create a Add node:
    Annotation 2019-12-26 005736
  9. Hold T and LMB Click to create a Texture Sample node:Annotation 2019-12-26 010504
  10. Hold U and LMB Click to create a Texture Coordinate node:
    Annotation 2019-12-26 010449
  11. Just press C to create a comment:
    Annotation 2019-12-26 005808

More UE4 Material Editing posts

UE4 – Basic Material Blending

Software:
Unreal Engine 4.24

The example explained in this article is creating a blend between a mud material, and a mud-leaves material using a mask (Alpha) texture.
>>
The scanned PBR materials in demonstrated in this post are from Texture Haven (texturehaven.com)

How does it work?
There is actually no blending of Unreal materials, but rather a regular Unreal material in which each of the parameters is defined as a linear blend between 2 different source values for that parameter.
We could create such a material blueprint that uses a Lerp (Linear Interpolate) node’s to provide each of the material parameters with a blend of 2 input textures/colors or parameters, connecting the alpha texture to all the Lerp nodes’s Alpha input, and effectively achieve blending of 2 different materials, but it would be a complex blueprint in which it’s very inconvenient to design each of the individual materials participating in the blend:
Annotation 2019-12-25 232734

This complexity can be greatly simplified by collecting each of the participating materials parameters into a Material Attributes data structure.
The Material Attributes data structure contains all the data needed to compile a material, and allows input, output, and processing of this data as a single blueprint data stream (connection).
For example, when the material parameters are grouped as a Material Attributes data structure, they can be blended by connecting them into a single BlendMaterialAttributes node, instead of “Lerping” (blending) between 2 inputs to create each individual material parameter, which produces an unworkable complex material blueprint like the previous example.

> To collect material parameters into a Material Attributes data structure, connect them into a MakeMaterialAttributes node:
annotation-2019-12-26-015532.jpg

> To create a blend between 2 Material Attributes data streams, use the BlendMaterialAttributes node:
* The Alpha parameter determines the weights of the blend (a black and white texture can be connected to it as the blend mask)
Annotation 2019-12-26 015717

> In order for the material output to receive a grouped Material attributes input instead of individual inputs for each parameter, select the material output, and in the Details panel, check the Use Material Attributes option:
matatts

Using the Material Attributes data structure, the blended material’s Blueprint in now much simpler and cleaner, while producing the exact same result as before:
Annotation 2019-12-26 021435

But designing 2 different materials within one material Blueprint is still far from being ideal..
What if we want to use just one of these materials on some surfaces?
What if the individual materials are not as simple as the materials shown here, it would be mush more efficient to be able to have one Blueprint for each of the materials allowing to focus on its development and preview it.
We can achieve this desired workflow by developing each of the materials as a Material Function.
Each of the participating materials is created as a Material Function with a Material Attributes output.

> One of the huge advantages of UE4’s material editing is that it allows us to preview a full material while developing it as a Material Function.
* This may sound trivial, but it isn’t. the Material Function isn’t compiled by itself as a material, it just produces data needed to define a material. in many other media production systems, this would have meant that you can develop data within the function but only preview it in the main material where the function is used.

> Learn how to create Material Functions

The Material Function defining the mud material:
Annotation 2019-12-26 024834.jpg

The Material Function defining the mud-leaves material:
Annotation 2019-12-26 024906.jpg

The Blend material using the Material Function nodes:
Annotation 2019-12-26 025111

Note:
When blending a non-metallic material with a metal material, the alpha values (mask colors) should be only 0 or 1 (black or white), otherwise blend areas that have a mid-range metallic value will make no sense visually.
> A RemapValueRange node can be used to force a color threshold on the mask texture or value.

Related:
Material Functions
Material Instances
Texture Painting

UE4 – Material Functions explanation and Example

Software:
Unreal Engine 4.24

Material Functions encapsulate shading flow graphs (material blueprints) into reusable shading nodes that have their own inputs and outputs.
This allows development of custom shading nodes, and saving the time it takes to recreate the same flow graphs multiple times or even copy and paste material flow graphs.
Common shading processes and operations that have to be performed in many different materials, and even multiple times in a single material can be defined as a Material Function for quick and easy re-usability.
Material functions can also be used to encapsulate a full material blueprint with a Material Attributes output. this provides a convenient workflow for blending different materials together.

In this post I’ll detail the steps needed to create and use a Material Function.
The Material Function example we’ll create, called “ColorAngleBlend” performs a commonly needed shading operation of blending 2 colors or textures according to the surface viewing angle (facing ratio).

The ColorAngleBlend Material Function will have the following inputs:

  1. color a:
    The color or texture appearing when viewing the surface at perpendicular angle.
  2. color b:
    The color or texture appearing when viewing the surface at grazing view angle.
  3. curve exponent:
    The steepness of the blend curve between the colors, 1 being a linear blend and higher values displaying color a at more angles “pushing” color b to be seen only at grazing angle.
  4. base color blend:
    The percent of color b seen at perpendicular view angle.
  5. normal:
    bump normals input.

The final “ColorAngleBlend” Material Function Blueprint:
* The internals of the “ColorAngleBlend” Material Function
Annotation 2019-12-24 151655.jpg

An example of the “ColorAngleBlend” Material Function node used to create a reach view-angle dependent color blend for a steampunk metal material:
Annotation 2019-12-24 152625

An example of the “ColorAngleBlend” Material Function node¬†used to create a reach color for a car-paint material:
Annotation 2019-12-24 152036

An example of the “ColorAngleBlend” Material Function¬†node¬†used to create a washed-out effect for a cloth material:Annotation 2019-12-24 151927
Steps for creating the “ColorAngleBlend” Material Function:

  1. In the content browser, create a Material Function Object and name it “ColorAngleBlend”:
    Annotation 2019-12-24 161420
    Annotation 2019-12-24 162132
  2. Double click the ColorAngleBlend Material Function to open it for editing:
    Annotation 2019-12-24 162209
  3. Click the background of the work space to deselect the Output Result Node,
    So that the Details panel on the left will display the Material Functions‘s properties.
    Type a description into the Description field, check the Expose to Library option so that the new Material Function will be available to all materials in the Palate and node search, and define in which node categories it should appear:
    Annotation 2019-12-24 162805
  4. Select the Output Result node and in the Details panel on the left set its output name to “color”:
    Annotation 2019-12-24 163948
  5. Add a Linear Interpolate (Lerp) node, a Fresnel node and a Transform Vector (Tangent space to World space) node to the Blueprint and connect the nodes like this:
    * The Lerp node will blend the 2 color inputs with the Fresnel providing view angle data as the alpha for the Lerp.
    The Transform Vector  node is needed to convert normal (bump) input to world space for the Fresnel node.
    Annotation 2019-12-24 164646.jpg
  6. Adding function inputs:
    Create 2 Function Input nodes, in their Details panel, name them “color a” and “color b”, leave their Input Type as default Vector3D, check the option Use Preview Value as Default, number their Sort Priority parameters 0 and 1 to make them appear as the first inputs of the ColorAngleBlend¬†node as it will appear when used in a material, and connect them to the Lerp node’s A and B inputs:
    Annotation 2019-12-24 165934
  7. Adding function inputs:
    Create 2 new Function Input nodes, name them “curve exponent” and “base color blend”, this time set their Input Type to Scalar, check the option Use Preview Value as Default, set their Sort Priority parameters to 2 and 3 and connect their outputs to the Fresnel node’s ExpoentIn and BaseReflectFractionIn inputs:
    Annotation 2019-12-24 171212.jpg
  8. Adding function inputs:
    Create the final Function Input node, name it “normal“, set its Input Type to Vector3D, check its Preview Value as Default option, set its Sort Priority to 4, and connect its output to the Fresnel node’s Normal input:
    Annotation 2019-12-24 171640
  9. Adding default inputs:
    Finally, add constant nodes to serve as default input values for the Material Function.
    A pure white Constant3Vector¬†(color) constant as the default value for “color a” input,
    A pure black Constant3Vector¬†(color) constant as the default value for “color a” input,
    A Constant with value 1.0 as the default value for “curve exponent” input,
    A Constant with value 0.0 as the default value for”base color blend” input,
    A pure blue Constant3Vector¬†(color) constant as the default value for “normal” input.
    > Tip for quick creation of constant value nodes
    Annotation 2019-12-24 172438
  10. Save the new Material Function.

To use the new ColorAngleBlend Material Function create a new material, in the node search start typing color… to locate the ColorAngleBlend node and create it, and connect it to the desired material input.

Annotation 2019-12-24 173747

Annotation 2019-12-24 173809.jpg

> Material Functions can also be used by dragging them from the Content Browser into the Material Blueprint.

Related posts:
UE4 – Procedural Bump Normals
UE4 – Material Instances
UE4 – Fresnel node
UE4 – Triplanar mapping

UE4 – RemapValueRange Node

Software:
Unreal Engine 4.24

Having to remap a value range is very common in designing shaders, whether it’s to perform a traditional “levels” operation on a texture, or use just a specific range of values in a float input.
The RemapValueRange node let’s us do just that. this node has 5 inputs:

  1. Input: The input value
  2. Input Low: Input mapping range minimum
  3. Input High: Input mapping range maximum
  4. Target Low: Output range minimum
  5. Target Height: Output range maximum

Mono Noise examples:

  1. The original noise pattern:0
  2. Mapping input 0 -> 1 to output 0 -> 1 obviously has no effect:1
  3. Mapping input 0 -> 1 to output 0.3 -> 0.7 reduces the pattern contrast:2
  4. Mapping input 0.3 -> 0.7 to output 0 -> 1 increases the pattern contrast:3
  5. Mapping input 0 -> 1 to output 1 -> 0 inverts the pattern:4

In this example RemapValueRange nodes are applied to a texture’s individual color channels to increase contrast (Levels):
> Note that this operation can be performed using a simpler graph by using float3d adding and multiplication operations on the texture color (this will be a subject for a different post)
> Note that a different remapping operation can be performed on each color channel of a texture to adjust its color balance.

Before the value remapping:5

After the value remapping tha value in each channel 0.1 -> 0.9 to 0.0 to 1.0:6

The same operation performed by multiplication by 1.2 and subtracting 0.1:7.jpg