Straight Camera Motion Path

I am trying to create a motion path that starts as a curve but ends in a straight line but haven't been able to solve it.  Enclosed is an image with the desired path and and image of the path create by hitfilm with three key frame positions.  Is there any way to make a line segment between two key frames straight?


  • Triem23
    Triem23 Posts: 20,070 Ambassador
    Use multiple points to control your camera. Based on your picture, I'm going to use X and Y axis for this explaination.
    So--create two new points for your camera. Name the one you're currently using "Camera Pivot Point." Put your camera at frame 1 and kill it's animation--we're going to rebuild it.
    Name one of the points "Camera X" Name the last point "Camera Y." Make sure all three points are in the same position. Parent "Camera Pivot" to "Camera X" and parent "Camera X" to "Camera Y."
    Ok, so, now, based on your curves above, you want the camera to go right, then up. Left-right is X axis, of course, and up-down is Y axis.
    So... you're going to animate each axis with it's own point. Let's say this is a 10 second shot and you want the camera to basically go right for three seconds, then up and right for four seconds and straight up for three seconds.
    go to frame 1. Turn on Position keyframing for Camera X and Y.
    go to second 3--create a keyframe for Camera Y and move Camera X to the right.
    go to second 7--move Camera X to the point where the curve ends and create a keyframe.
    got to last frame--Move Camera Y to the point where the dolly ends.
    Now... If you get this concept of using a different point for each axis of movement, then you can start to finesse things and get really good camera moves that you just can't get with one point: By splitting the control you don't have to have the x and y moves start on the same frame, and you can use different interpolation curves on each axis, which lets you build up much more realistc and dynamic moves.
  • Jeroni
    Jeroni Posts: 38
    Thank you Michael,
    That made a huge difference.  I guess I will never key frame camera location again!
  • Triem23
    Triem23 Posts: 20,070 Ambassador
    You're welcome:
    To expand on this technique a bit, I often add MORE points to a camera rig:
    So--My camera is usually parented to a point I call "Camera Tilt." Camera Tilt represent the head of a virtual tripod. Specifically, the joint to look up and down. "Camera Tilt" is parented to "Camera Pan." "Camera Pan." represents the part of the tripod head that lets the camera turn from side to side. Splitting these into two points makes my camera behave a lot more like it's on a tripod. (Hitfilm always interprets rotation in the order of X, then Y then Z, But a camera on a tripod is going to rotate Y first, then X.) "Camera Pan" is then connected to whatever my camera move points are (If the camera is staying on a plane, like a camera moving on dolly tacks, I need two move points--X and Z. If may camera is moving on multiple planes, like a crane shot or a free moving camera I might need X Y and Z.)
    And, just to get super-fancy, let's take a look at this picture.
    So--that's a cam on a tripod--as you can see the parts of the tripod that tilt and pan are several inches away from te body of the camera. If you rotate the Hitfilm camera, it rotates around the "nodal point." of the lens. (The "nodal point" is the actual focal point of the lens, more or less.) But, as you can see from the picture, most camera mounts DON'T rotate around the nodal point....
    Therefore, if you take the "Camera Pan" and "Camera Tilt" points and put them a little bit behind and a bit more below the camera position, when you pan and tilt your Hitfilm camera, you'll get that little bit of movement drift a real camera would have, which will make your CG camera moves feel more realistic.
    The only thing I ever directly animat on the actual camera is Z rotation. Everything else is part of a point rig. As you discovered, it takes longer to set up this kind of rig, but you get better camera moves.