Effects question: Compositing spaceship over car?

Discussion in 'Fan Films, Fan Audio & SciFi 3D' started by Ridley Solo, Oct 19, 2011.

Moderators: AdamBertocci
  1. Ridley Solo Jedi Master

    Member Since:
    Aug 27, 2010
    star 4
    Hello!

    I just had a question regarding effects.

    For a sequence in my film, a Jedi is suppossed to be fixing a spaceship. Since we're not allowed to bring any sets on location and our greenscreen studio isn't big enough for the shots, my idea was to use a car on jacks as a placeholder and drape green cloth over it.

    My question is, would the car need the green to be comped out and the ship comped in, or would it work with just the car?
  2. BruceM Jedi Padawan

    Member Since:
    Mar 8, 2006
    star 4
    You will have an issue with the greenscreen if their is any green in the location. Unless you specifically need some direct contact (that can't be faked through acting), then I wouldn't worry about a greenscreen or a car at all. However, it would require some roto if the ship is behind the actor but in front of the background. For your ship, are you going to comp in a physical or a cg model? If you are doing a CG ship, make sure you get on location:

    1) a clean plate of the background (no actor, no car, nothing). If you have camera moves this might be a little more difficult, unless you have some sort of motion control with a dolly or something

    2)Reflective IBL of the scene. Normally done one of two ways, the fastest way is to get a chrome sphere, and shoot it underexposed, normal, and over exposed. After wards you take the 3 pictures and merge them into an HDR in photoshop or similiar program. You can then use this as an IBL in your CG program for reflections of the scene. onto the ship. Also keep in mind it is a good idea to shoot the chrome ball from the same angle as the plate.

    3)If you can, also shoot a grey matte ball. This isn't 100% necessary, but it will give you lighting reference for when you create the lighting in your CG program
  3. Ridley Solo Jedi Master

    Member Since:
    Aug 27, 2010
    star 4
    Wow, thanks for such a detailed answer! :)

    -The actor is in fact going to be leaning against the 'ship'
    -The 'layers' of the scene will go actors > ship > background
    -The ship will be CGI

    Just a couple of questions.

    How does one make a chrome/gray ball for lighting reference? :confused: If not, how much would they cost and where would you find them?
  4. BruceM Jedi Padawan

    Member Since:
    Mar 8, 2006
    star 4
    I read online a few days ago that a silver Christmas tree ornament ball could be used. The top hole is then mounted to some sort of tripod or stick. As for the grey ball, if you can't find a matte dull mid gray ball, just take a smooth ball and evenly paint a mid grey color on it. The key for the grey ball is dull with no glossiness.
  5. Ridley Solo Jedi Master

    Member Since:
    Aug 27, 2010
    star 4
    Cool!

    So, I'll add these to the shopping list: Large silver Christmas tree ornament ball, smooth ball (?), flat gray paint, and woodel dowel.

    Thank you! :)
Moderators: AdamBertocci