What do you mean by "projectionplane" ?

A projection plane is simply a 1 by 1 unit facet object.

The idea is to link ufo's world (2D) and the scene world (3D) in an easy and open way.
This projectionplane is used in RSMB from revisionfx to transmit 3D scene infos to the ufos.

You don't need specials tools to create and use a projectionplane.
Just create a 1 by 1 unit grid , place the origin at the bottom-left of the object.
Any objects parented under the projectionplane will have their [x,y] coordinates ranging between [0,1] when lying inside the plane.

If a projectionplane is specified inside an ufo , these [x,y] coordinates are mapped directly to the screen coordinate system of the ufo.

If you branch select the projectionplane and scale it to the ratio of your image resolution you will have a 3D representation of this image in your scene while keeping the [0,1] range intact. (scalx to 7.2 and scaly to 5.76 for a pal image for exemple)

lmProjectionPlane

lmProjectionPlane creates a projectionplane linked to a 3D camera. The projectionplane is placed orthogonal to the camera and is constrained to fit exactly the frustrum (fov) of the input camera.You can define a distance from camera node to the projectionplane center.
You can then create nulls parented under the projectionplane or project a group of 3D objects on the projectionplane.

Download and install

Download lmProjectionPlane.xsiaddon then drag and drop inside XSI.
The plugin will be accessible in Get>Camera>Create lmProjectionPlane.

If you prefer to download the self-installing jscript plugin, here it is: lmProjectionPlane.js.
You just need to copy this file in your \Application\Plugins directory (either in your user directory or your workgroup directory).

Usage

select a camera and Get>Camera>Create lmProjectionPlane. The projectionplane is created and parented under the camera node. A curve figuring the projectionplane location is also created if you want to hide the projectionplane when rendering or shading.

Parameters

• Distance : distance between the camera and the center of the projectionplane
• Offset x,y : offset in x,y of the projectionplane

• Add null : adds a null under the projectionplane
• Project Group : projects a group of objects on the projectionplane . select a group in your scene.

note : if you animate the visibility of the objects , it will be copied to the projected ones.

By using lmProjectionPlane you can easily transfer 3D points from a matchmoved scene to an ufo like RSMB from revisionfx. You can find an exemple scene of how using lmProjectionPlane to help RSMB estimating motion in the RSMB for XSI tutorials exemples here

Disclaimer

The software is released as is, without any written or implied warranty. The software cannot be redistributed without permission from LaMaison. The program will not be supported. LaMaison is not responsible for any damage or loss of data incurred by the use of this software. lmProjectionPlane was developed by Aloys Baillet for LaMaison.