Catcher Node

Catcher is a special material that intercepts Texture mode projections and turns them into a regular texture map. Unlike Light or Ambient Light mode projections (which light the geometry), Texture mode explicitly requires a Catcher to be connected to the material of the target object.

Key advantage: unlike Light mode, Texture mode supports alpha (it cuts the geometry according to transparency) and does not need lighting to be enabled in the Renderer 3D.

• Effects Library: Tools > 3D > Texture > Catcher
• Quick add: right-click in the Node Editor → Add Tool > 3D > Texture > Catcher

Without a Catcher, the Projector 3D in Texture mode produces nothing - no visible effect. The Catcher tells Fusion: "this object is a valid receiver for Texture mode projections".

Light or Ambient Light projections do not need a Catcher - they automatically light everything inside their cone. But they ignore the alpha channel.

Rule: if you want to project an image with its alpha onto an object, or if you do not want to depend on the scene lighting → Texture mode + a Catcher on the target object.

The Catcher has no input. Its output connects directly to the MaterialInput of a 3D geometry.

Complete pipeline for a Texture mode projection:

Catcher ──→ Shape 3D (MaterialInput)
                       ↓
                   Merge 3D
                       ↑
MediaIn (image to project) ──→ Projector 3D (mode = Texture)

The target object (Shape 3D here) carries the Catcher as its material. The Projector projects the image in Texture mode → only the part that intersects the Shape 3D carrying the Catcher is visible.

Color Mode (Software Renderer only)

Controls how several projectors combine their color values (e.g. Average, Add, Max).

Alpha Mode (Software Renderer only)

Handles how alpha channels combine when several projections overlap.

Threshold

Excludes low values from the accumulation. Keeps near-black pixels from dirtying the render.

Restrict by Projector ID

When enabled, the Catcher only receives projections from projectors with the matching ID. Useful to isolate one specific projector when several are active in the scene.

Material ID

Identifier for the Renderer's Material ID AOV.

• Matte painting with alpha cutout - project a building image with its windows in alpha (masked out) onto a cylinder. The windows become transparent, revealing the modeled interior behind.
• Clean set extension - project a filmed plate onto rough matching geometry. The alpha lets you cut precisely without spilling over.
• Video projection on a 3D screen - video MediaIn → Projector 3D in Texture mode → Catcher on a plane = the screen plays the video.
• Selective multi-projection - several different projectors, each with an ID, and several objects with different Catchers. Restrict by Projector ID lets you route who receives what.
• Projected spec map - advanced trick: connect a Catcher to the Specular input (or Reflection, Bump) of a material instead of Diffuse. The projection then acts as a spec map, not a diffuse map.

• Texture mode = alpha supported - that is the main reason to use a Catcher. If you do not need alpha, direct Light mode is simpler (no Catcher).
• Catcher on an input other than Diffuse - a powerful trick: connect it to the Specular, Reflection or Bump of a material so the projection only affects that channel. E.g. a Catcher on Specular = a projection that creates specular highlights only where the image is bright.
• Restrict by Projector ID - essential when several projections coexist, to keep everything from mixing. Name the IDs logically.
• Software Renderer required for Color Mode and Alpha Mode. OpenGL ignores them.
• No input - the Catcher works as a "receiver". It does not hold the image itself; the Projector provides it.
• For Light mode projections (no alpha, with lighting), no Catcher is needed - the Projector lights the geometry directly. See the Projector 3D page for the 3 modes.