Ray Portal BSDF

Cycles Only

The Ray Portal BSDF node transports rays that enter to another location in the scene. It can be used to render portals for visual effects, and other production rendering tricks.

It acts much like a Transparent BSDF: render passes are passed through, and it is affected by light path max transparent bounces.

Note

• The Ray Portal BSDF only allows rays to pass through it in one direction. Add a second portal at the target location to make rays go in the other direction as well.

• Light sampling does not work efficiently through portals. This can lead to increased noise from lights on the other side of portals. Particularly small lights may be very noisy, or not pass through at all.

Inputs

Color

Tint rays passing through the portal.

Position

Ray start position at new location. Defaults to the current position, matching the Position output of the Geometry node.

Direction

Ray direction at the new location. Defaults to the current view direction, which is the same as the negation of the Incoming output of the Geometry node.

Properties

This node has no properties.

Outputs

BSDF

Standard shader output.

Examples

One use case for the Ray Portal BSDF is to connect two spaces together to create effects like a portal to an alternative dimension, or “impossible spaces” where something is bigger or smaller on the inside than expected.

To set up a Ray Portal BSDF for a technique like this, augment the Position and Incoming outputs of the Geometry node to set the exit point and direction of the ray through the portal. Here are some examples:

Simple Offset

Portal

Camera Feed

Along with augmenting rays, the ray position and ray direction can be replaced, for effects like a camera feed on a screen.