Setup 3D scene locked off camera composite

What is the best way to start setting up the shot so everything lines up?

I have shot some green screen footage with a locked off camera, and having trouble placing the 3D objects in it.

I have modeled a 4x8x2 cube as placeholder( our platform is the same size) but cant seem to fit it properly back into the locked of scene.

I seem to be going back and forth, if I adjust the cube to the ground plane I cant get the live action to line up.

 

 

 

 

Comments

  • How do I add images on windows the insert/edit image dialog on has a source textbox

  • Triem23
    Triem23 Posts: 20,698 Ambassador

    I'm not certain what your second question means (adding images on windows). 

    The first question... Well, it's all about matching the virtual camera to the real camera. When using a tracker like mocha, the software will try to figure out the camera FoV. Mocha Pro also has tools for correcting lens distortion (real lenses will have some image distortion from lens curvature), although lens distortion is usually only an issue at extremes of wide and telephoto. 

    Anyways, I think your starting point is playing with the Zoom settings of the Hitfilm camera.  From what you describe, that's the place to start. I'll have to dig it off a drive, but a Hitfilm user a couple of years ago came up with an equation to convert real focal length to Hitfilm's focal length. It's not 100% accurate (it doesn't take lens distortion into account), but it'll get you close. Helps if you know the focal length of the lens you used. If a DSLR/Mirrorless, then this is just looking at the lens, then checking your camera specs for any crop factor. If a camcorder, then the manual will give you the equivalent zoom range of the lens. 

  • tddavis
    tddavis Posts: 5,204 Expert
    edited March 2017

    @_ERIC_  As to your 2nd question, you have to upload images to an off site cloud like OneDrive or Googledrive or Dropbox etc. and then post a share link here in the forums.  Hitfilm forums doesn't have a a dedicated upload path for images.

    On the first, I am not sure but it sounds like you might be using the arrows in the viewer window to move your object (I have seen it do similar reactions), so you could try using the the controls tab to adjust the X-Y-Z position data directly which is how I usually get around this when I have something like it happen. Hope I helped in some way.

  • Triem23
    Triem23 Posts: 20,698 Ambassador
    edited March 2017

    And.... the aformentioned equation.

    "So the formula to calculate zoom should still be the same to match real world footage

    For standard 1920 x 1080p pixel aspect ratio 1

    hfzoom = CameraLens(mm) * VideoWidth(px) / CameraSensorWidth(mm) * PixelAspectRatio

    So for a real life 35mm Lens on my crop frame GH3 the hitfilm zoom would be
    35*1920/17.3*1 == 3884.39"

  • tddavis
    tddavis Posts: 5,204 Expert

    I may have misunderstood the second question myself.

  • ___ERIC___
    ___ERIC___ Posts: 7
    edited March 2017

    Thanks.

    Yes, the 2nd question was for uploading images here, I will post some so I can be more clear about questions.

    Composite

    The camera we used:

    hvx200A shot in 1080p/24

    Focal Length 4.2 to 55mm (we shot all the way  wide )

    Field of View: 32.5mm

    For that formula,

    1. Would I use the dvcpro codec size 1280 or 1920

    2. it has 3 1/3" sensors round down to 8mm or up to 9mm?

    55 * 1280/8 * 1.5

    I am editing in FCPX and have exported a frame to HitFilmPro to line up everything if that makes a difference.

    Once the formula is worked out, do I import the 3d cubes and set up the camera to that, then add the image and move the image to line everything up?

     

  • looks like my comment was deleted

    ********************

    Thanks.

     

    Yes, the 2nd question was for uploading images here, I will post some so I can be more clear about questions.

    http://s38.photobucket.com/user/rumpotPhoto/library/?sort=3&page=1

     

    The camera we used:

     

    hvx200A shot in 1080p/24

     

    Focal Length 4.2 to 55mm (we shot all the way  wide )

     

    Field of View: 32.5mm

     

    For that formula,

     

    1. Would I use the dvcpro codec size 1280 or 1920

     

    2. it has 3 1/3" sensors round down to 8mm or up to 9mm?

     

    55 * 1280/8 * 1.5

     

    I am editing in FCPX and have exported a frame to HitFilmPro to line up everything if that makes a difference.

     

    Once the formula is worked out, do I import the 3d cubes and set up the camera to that, then add the image and move the image to line everything up?

  • Triem23
    Triem23 Posts: 20,698 Ambassador

    Once I know the camera...

     

    Lens is 30.3mm (35mm lens equivalent).

    Video width 1280.

    Don't drop the fraction. 8.467mm

    Pixel aspect ratio is 1.5 (1280 stretched to 1920)

    30.3*1280/8.467*1.5=6870.911

    Ideally I would line up the cube to the plate first. 

  •  Is there a trick to that? I can not get the perspective to line up with the floor.

    http://s38.photobucket.com/user/rumpotPhoto/media/chamberCubePerp_zps1lnwgwlr.png.html

  • Triem23
    Triem23 Posts: 20,698 Ambassador

    I'm thinking you shouldn't have moved the Hitfilm camera first... 

    Take a look at this tutorial. It's on setting up camera projection, but it's also the way I'd match a floor plane for any video with 3D models.

  •  I cant seem to line up the ground plane like on that tutorial.

    http://s38.photobucket.com/user/rumpotPhoto/media/chamberProjectionStart_zpsyku2nkjq.png.html?sort=3&o=1

    Here is the rough digital set

    http://s38.photobucket.com/user/rumpotPhoto/media/chamberSetPNG_zpsees3e5oa.png.html?sort=3&o=0

    Shouldn't it be fairly trivial to line up a ground plane, match the camera angle, and the 3d cubes should line up with the physical cubes?

    I will keep trying with the project tutorial, but the end goal is to line up the plate, then key it out, leaving the live action over the 3d set but interacting with the physical geometry.