This page guides you through the steps of making a Shadow Catcher object with V-Ray for Blender.
Overview
The V-Ray shadow catcher is a Matte object that is not directly visible in the scene but receives shadows. This approach is ideal for achieving a photorealistic render, compositing a 3D object with a shadow on top of the environment map, or just a backdrop.
The scene here is set up using a Finite Dome Light with an attached HDRI map from the Chaos Cosmos Browser. The car geometry is also imported from Cosmos. The Camera has the V-Ray Physical Camera Attributes enabled.
Click on the button to download the scene and follow along with the steps:
Without Shadow Catcher
With Shadow Catcher
Create the Shadow Catcher Object
Add a Plane geometry under the object that is casting the shadow. At the end of this tutorial, the geometry will be invisible and will only receive shadows.
You can see that now the object is casting a shadow, but the plane is visible, so it does not look like the car is on the street.
See how to create a shadow catcher using Matte properties.
Steps
1
Select the plane. Go to the V-Ray Node Editor and open the Object Node Tree. Click on Use V-Ray Object Nodes. You will see the V-Ray Object Output node appear in the Node Editor.
The V-Ray Node Editor is available only when the render engine is set to V-Ray. For more information, see Activate your Product.
2
Create a V-Ray Matte Properties node. It is located under the Add menu > Object Properties. Connect the node to the Matte input socket of the V-Ray Object Output. This way, the Matte properties will be applied to the plane.
3
Go to the Matte Properties' parameters. They are in the Node side panel of the V-Ray Node Editor.
- Set the Alpha Contribution to -1
- Enable the Shadows and Affect Alpha parameters
- Set the Matte for Secondary Rays parameter to With Projection Mapping
Alternatively, you can access the Object Properties from the Object tab > V-Ray Object Properties.
Here are the same properties in the Object tab, where you also need to enable Matte Surface, to be able to access these settings.
This is how the render looks in the end. You can see the car geometry is now casting a shadow in the scene; the plane under it is not visible, but only receives shadows. Thanks to the Matte for Secondary Rays, the plane is also not visible in any secondary reflections on the car.