Tutorial Using 3DS Files for Output Correction

Using 3DStudio files for output correction

With MXWENDLER you can use 3DStudio files for output correction. The physical approach behind this perspective correction is a reverse light ray.

1. A viewer wants to see a perfect projection.
2. The viewer position is known.
3. The projector position is known.

The solution is to do a reverse projection:

1. Imagine a virtual projector from the viewer’s position.
2. Set up the virtual projector to project a perfect image for the viewer.
3. Record this projections from the real world projector’s position.
4. In the real world, project the resulting image from the real projector.

{{#mpdftags: pagebreak}} {{#mpdftags: pagebreak}} To realize such a projection correction, it is first necessary to set up the entire scene in a 3D modeling tool such as Blender, which is capable of exporting 3DS files. The created scene must contain

1. One or more viewers. These are represented by

   → A sphere representing the viewer’s position, named ‘viewer_1’

   → A cube representing the viewer’s line of sight, named ‘viewer_1_tgt’

2. One or more projectors. These are represented by

   → A sphere representing the projector’s position, named ‘beamer_1’

   → A cube representing the projector’s line of sight, named ‘beamer_1_tgt’

3. The target object, named ‘target’.

Please note that e.g. Cinema 4D has an object name length restriction of eight characters.

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{{#mpdftags: pagebreak}} To use this scene in a MXWENDLER correction setup, it is first necessary to export this into a .3ds file, and assign this to a keystone element.

1. In blender, export using File Export → 3DStudio .3ds
2. In MXWendler, switch to the keystone tab.
3. Select a single element.
4. Open the ‘Element’ tab, click the ‘Load 3DS’ button.
5. Select the exported .3ds file.
6. Choose the desired beamer and viewer.
7. Choose the necessary beamer and viewer FOV (lens opening angle).

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