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Hopping around with bezier paths in Motion 4
Stephen, oh, Motion Master (or anybody else at this point): how do I do this without losing my mind?
The general idea: you’re taking a trip between 5 cities in roughly a circle. I use the bezier tool to create a curved, arch-like path from Springfield flying South and West to a city near the Missouri border, and I’m going to keyframe that arc-ing path so it traces thru the air with a shadow falling on the map below. Somehow I got that much done on my own, and animating it by keyframing the start and endpoint reveals works fine, but it took too long to position the curved line in 3-d space at a jaunty angle while keeping the end points anchored to the spots on the 3-d map.
Picture of what has gone on so far:
Now, I need to go from the first arc’s endpoint, up to Champaign, near the center of the state, with a second, similar arch-like path. Then to Bloomington-Normal, Peoria, and finally back to Springfield. At the end,all the arches will be connected at their endpoints and all visible together, looking something like a roller-coaster. Getting it to line up in 3-d space is making me crazy.
Any tips for a faster, more controllable way to get these done? I have a number of these bouncy paths to create over a few seconds. When I look at them in perspective view, their positions are way off of reality, they are off in the z axis as well as one other axis.. I can bend them around in the camera view to look good from one narrow angle… but eventually, this entire map is going to do a slow rotate with camera moves, so if the arches don’t actually hit their spots for real, the “cheated” line-ups will give themselves away instantly as the viewpoint moves. It’s frustrating to feel so close to getting it right, but not getting the expected results.
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4 Replies
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Add a Write On behavior to the B-Spline line (arrow) and that will animate it so it starts from nothing and then looks like it is writing onto map. Then you don’t need to keyframe anything and it is very smooth. Duplicate the b-spline line like you did and changes its color to black like you did for the shadow. MOve the control point like you did so the shadow is the right angle. They will both have the same write on behavior so they will animate together. Duplicate for the other lines. Hope this helps. Best of luck.
Stephen Smith
Utah Video ProductionsCheck out my Motion Training DVD
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That much I can figure out. It is drawing the next spline and getting it in the right position in 3 d space that is messing me up. Tried just copy-pasting the first one, but each leg of the trip needs too much difference in proportions.
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Today I’m finding this task is easier to do as a stroke than as drawing a bezier path.
Using the stroke brush, I draw a curved path freehand from point to point, and don’t sweat any little wiggles in the line. In the Geometry tab is a slider for “roundness” that will smooth it all up into a nice curve. I am building each path in its own group. Then I’m rotating the curve in z-space to make it arch over the map. Rotation will change the place where the end points hit, so I go to the first and last set of coordinate points and drag those to re-locate the ends of the arc. Keyframing the first and last point offsets draws the line to go with the voiceover timing.
This is still taking too darned long but it’s getting where I needed to go.
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You might try the following:
1. Start with your camera directly overhead. (No rotation on any of the rotation axes.)
2. Draw a line from the start point to the end point.
3. Make a vertical guide and rotate the line you just drew so that it is straight up and down. (using the guide to help.)
4. Add a point in the middle somewhere and pull it out. (You can fine tune the curve later.)
5. Adjust the Y rotation til it’s 90 degrees or whatever angle you want. (Make sure you are adjust around the World Axis.)
6. Move and rotate the line back into place. You can now adjust the curve point as much as you need without messing up the start and end points.
7. The write on behavior will take care of the rest.
I tried this out and it took only a couple of minutes to do one line with, so it’s pretty easy.
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