Cool trick from Brandon Davis

I learned a really cool trick from Brandon Davis while attending his masterclass at Siggraph.
Brandon is an old friend who has done film effects and commercial work with 3ds Max and Houdini for years.
His credits include the movies Armegeddon and Day After Tommorrow, I think he still works at Digital Domain.

His class was on making water, primarily ocean water. His trick was a method to automatically remove everything not in the camera's view. Here's how"

1. Create a Camera
2. In the Top Viewport, draw a trapezoid to match the cone of the camera. Call this object VolumeSelectObject
3. Extrude the Trapezoid to match the cone of the camera in the Front/Left viewport.
4. Use Vertex editing so you have an close match of the proportions of the camera cone.
5. Link the VolumeSelectObject to the camera.
6. Apply a Volume Select Modifier to the scene geometry.
7. In the Volume Select Modifier select vertices based on the Volume Select Object.
8. Invert the selection
9. Add a Delete Mesh modifier to the selection.

Now wherever the Camera travels in an animation, the Delete Mesh will be applied directly to everything unseen by the camera.

You can use the same idea to APPLY a Subdivide Modifier to ADD detail, rather than remove it. You can make a second volume select object that doesn't extend as far from the camera to control the range for the extra detail. This allows anything close to the camera to have additional tesellation.

Neat trick, huh?