Eyeon:Manual/Fusion 6/3D/Projection Mapping

Projection is a technique for texturing objects. Images are mapped onto objects using a Camera or Projector tool. This can be useful in many ways; texturing objects with multiple layers, applying a texture across multiple separate objects, projecting background shots from the camera's viewpoint, image-based rendering techniques and much more.

Projected textures can be allowed to "slide" across the object. If the object moves relative to the Projector 3D, or alternatively, by grouping the two together with a Merge 3D they can be moved as one, and the texture will remain locked to the object.

Basically, there are three different ways to do projection mapping.

Using the Projector/Camera tool set to project light. The projection is done per pixel

In this mode the Projector or the Camera acts as a light with all lighting features. This mode requires per pixel lighting and lighting must be enabled in order to see some results. It is possible to choose if the projector behaves like a spotlight or an ambient light. Alpha channels cannot be projected. Overlapping projections add together like any other light tool. An internal clipping plane (at around 1.0 distance from camera) limits how close the Projector/Camera can get to the projection receivers. Have a look at the Projector tool documentation for more details.

Using the Projector/Camera tool set to project a texture onto a Catcher material

In this mode the projecting tools acts as real texture projectors. There is no light contribution anymore. As a consequence a Catcher tool is required in order to receive the texture and apply it to a material. Only objects using this material will receive the projection. This offers some advantages like the projection of alpha channels and texturing other channels like specular color or roughness. Overlapping projections can combined in various ways (mean, median, blend) via the Catcher tool. An internal clipping plane (at around 1.0 distance from camera) limits how close the Projector/Camera can get to the projection receivers. This mode needs per pixel lighting.

Using the UVMap tool with its MapMode set to Camera/Projector

This mode requires a camera and an UVMap tool downstream of the objects where to apply the texture. The UV Map tool gathers the information from the camera and creates a new UV-map for the upstream objects. These are used for texturing. In order to work properly, the object must be tesselated sufficiently.

Textures are assigned to the object or its materials like any other texturing technique. It supports alpha channels as well as bump mapping. The UVs can be locked to the vertices at a chosen frame. This locking only works as long as long as the mesh is not changing over time since Fusion must be able to match up the mesh at the reference time and the current time. Its transform can be changing, but the mesh itself cannot be. To be more specific, vertices may not be created or destroyed or reordered. Eg. projection locking will not work on particles because they get created/destroyed, a cube with its tesselation slider animated, a duplicate tool with its time offset set to non zero so addition meshes get created over time.