# How to use a reflective ball to capture reflections?

Hello, my question is :

How do I use a reflective ball (Christmas Ball/Chrome Ball) to capture the reflections from a location and map it to blender, so I can composite objects into my scene with reflections. You see them do it on Star Wars and Garfield.
Say I want to create a space ship that is reflective and motion track it into a shot of me panning along a road. I would want to somehow capture what would be reflected onto the spaceship and map it to the ship.

Thanks,
Josh!

here is a very good example of what you want…http://www.youtube.com/watch?v=afUio1GMeFg&feature=related

You need to describe your shot and your objective in much more detail.

There’s a reason, though, why spaceships are generally not shiny and do not fly close to the ground . . . To do it right you’d have to get a light plane up in the sky or a very tall truck and film some live footage of the ground from the sky. Could get ugly.

sorry that link wasnt really appropriate…i realized later…i tried to do a scene with environment mapping…it did provide a reflection of the scene my object was in but you want to reflect the live stuff onto the tracked object that is composited into the scene…maybe an animated material with a reflection map of the scene…you got me thinkin

As of yet, there is no motion camera that could shoot an HDRI of the reflective/chrome ball in motion so the only way to do what you want would involve a combination of methods and/or tricks but the answer to your question depends heavily on:

A) how relfective you want the spaceship to be (ie: do you just want the illusion of something casting reflections on the ship or do you want a complete mirror image within a window or panel of the ship)
B) the complexity of the geometry that you want the reflected image to show up on (a simple window, or intricate details of the ships design?)
C) how close the camera is to said reflections and therefore how “real” you want them
D) the complexity if what you want to see reflected. Ie: is there movement within the reflections aside from the motion of the ship travelling through a static environment (ie people or other objects moving)

To simply get reflections of the still environment that is around the ship then you want to get an HDRI image to use as an Environment Texture. There are several independent tutorials for the different steps for the process (shooting the chrome ball, creating an environment texture, etc.) Let me know if you need URL’s.

However, if you want a more specific reflection involving precise movement ( ie: the reflection of the camera operator who supposedly shot the footage of a ship) then you’d have to do a series of compositing and/or texture tricks, but the first step is to use a second live action camera to actually shoot the footage that you want to eventually see reflected. Then, depending on how big, distorted, transluscent, etc you want it to be, you either apply that footage as a texture to the specific geometry that you want it in or (easier and recommended) track that footage back onto the ship in a compositing app. Ive seen Sebastien Konig do a convincing corner pin track onto a movie screen but thats a very simple surface. If you’ve got anything beyond a 2D plane that you want to reflect then you’ll want to use a dedicated compositor such as After Effects, Nuke, Shake, etc. which will give you much more flexibility. Either way, youll need to set up you render layers apppropriately to get the results you want.

As you can see, the answer depends heavily on what it is you want to see and what your shot is like so the more specific you can get, the more precise I/we can be with answers. Meanwhile, hope this helps the thought process.