Method

The shadow catcher node captures shadow information from lights cast on to the surface of an object that has the shadow catcher material applied to it.

The captured shadow information can then be rendered separately onto surfaces of a scene using the layers composite blend modes alpha channels.
This will give you the ability to render shadows onto objects not in the scene – for instance on real-world objects or floors in AR projects.

An example shadow catcher project can be found in Notch’s shipped samples list.

This example uses layers to show the shadow catcher node working.
Layer 1 is the background layer containing a background image the shadow catcher will project on.

Layer 2: Shadow Catcher skylight layer shows a scene with the shadow catcher setup with a skylight.

Shadow Catcher using a skylight
Shadow Catcher skylight Nodegraph

Layer 3: Shadow Catcher Spotlights layer shows a scene with the shadow catcher node setup using spotlights.

Shadow Catcher using Spotlights
Shadow Catcher Spotlights Nodegraph

BRDF

Name Description
Shadow Catcher Colour The colour of the shadows.
Baked Diffuse Intensity The intensity of the diffuse texture.
Use Baked Diffuse Map As Ambient Occlusion Sets the diffuse map as an ambient occlusion map.

Settings

Name Description
Lit Toggle whether the material can be lit by lights in the scene.
Casts Shadows Toggle whether the objects the material is applied to casts shadows.
Unseen By Camera Toggle whether can be seen by the camera.
Back Face Cull Mode Changes which directions the face will be visible in.
  • Double Sided, Both sides of the material will be rendered to the surface.
  • Show Front Faces, Only the front side aligned with the normal will be rendered.
  • Show Back Faces, Only the back side opposite to the normal will be rendered.
Flip Polygons Toggles whether the polygons are flipped on the material.
Wireframe Toggles whether the polygons are wireframe on the material.

Displacement / Normals

Name Description
Normal Smoothness Change how much smoothing is done to the edges of the object.
Smoothing Angle Sets the smoothing angle of the mesh faces. The higher the smoother the result.
Normal Map Strength Change how strong the normal map effect is. Only functions if a normal map is selected in the “normal map” attribute, and the normal map mode is set to “normal mapping”.
Normal Map Mode Change how the normal map affects the material.
Normal Map – Invert Normal X Invert the normal map along the X axis.
Normal Map – Invert Normal Y Invert the normal map along the Y axis.
Normal Map – Invert Normal Z Invert the normal map along the Z axis.
Displacement How Much the displacement map affects the object.
Displacement Offset Offset displacement amount for the displacement maps.
Parallax Amount Enables Parallax Occlusion Mapping, and sets how much the material is displaced by it.
Displacement – Use Polygons UVs Uses the Polygon UV’s to fix seams where the UV Map can wrap.
Displacement – Fix Tessellation Seams Can fix tessellation seams where displacement maps are sampled per vertex, and can wrap across polygons.

Texture

Name _.Description
Diffuse Map Select a source image to add a diffuse map to the material.
Displacement Map Select an image to displace the mesh based on the luminescence values of the image. Can be used with the “Subdivision Levels” attribute in the 3D Object node.
Alpha Map Select an image to control the alpha values of different areas of the material, based on luminance.

UVs

Name Description
UV Scale X Scale the UV texture along the X axis.
UV Scale Y Scale the UV texture along the Y axis.
UV Offset X Offset the UV texture along the X axis.
UV Offset Y Offset the UV texture along the Y axis.
Diffuse UV Scale X Scale the Diffuse UV texture along the X axis.
Diffuse UV Scale Y Scale the Diffuse UV texture along the Y axis.
Diffuse UV Offset X Offset the Diffuse UV texture along the X axis.
Diffuse UV Offset Y Offset the Diffuse UV texture along the Y axis.
Texture Filter Mode Controls how textures used by the material are filtered – through point sampling, linear filtering or anisotropic filtering.
Texture Wrap Mode U Controls how textures used by the material are wrapped when the U value range exceeds 0 to 1.
Texture Wrap Mode V Controls how textures used by the material are wrapped when the V value range exceeds 0 to 1.
Diffuse Texture Filter Mode Controls how textures used by the material are filtered – through point sampling, linear filtering or anisotropic filtering.
Diffuse Texture Wrap Mode U Controls how textures used by the material are wrapped when the U value range exceeds 0 to 1.
Diffuse Texture Wrap Mode V Controls how textures used by the material are wrapped when the V value range exceeds 0 to 1.
UV Remap Filtering Enables filtering for remapping UV’s. Only functions with eligible textures.
Texture Mip Bias Bias the distance at which Mip Maps are swapped for original textures.

Misc

Name Description
Motion Blur Velocity Scale Scale how much motion blur is affected by the objects movement.
Glow Amount Control how much the object glows.
Density How dense the material is. Used in sub-surface scattering, and glass shading.

Ray Depth

Name Description
Use Global Settings When enabled, the internal settings will be ignored and the global settings for bounces will be used.
Max Diffuse Depth Sets the max diffuse bounces for the material.
Max Glossy Depth Sets the max glossy bounces for the material.

Outputs

Output a material that can be used by any node with a material input.