CompuServe Thread

Mike, rereading my reply, I can see how terse it was. Here's an expanded explanation. Imagine a rollercoaster; this is your path. Along the coaster, 3 cars travel, all linked together. You (the camera) are in the last car. You have your gaze fixed on the second car. As the cars travel along the path, the lead car will always turn or dip first. The second car will follow, which means that from your point of view, the first car will be somewhere in the center of the image, except it will "lead" your viewpoint by a second or so. This follows the natural lag we find in "Top Gun" for example, when jet A is being chased by jet B. (The camera is in jet B) Pilot B will always be a split-second late in reacting to pilot A, causing jet A to bob and weave around the center of the image; yet, both planes pretty much follow the same flight path; after all, pilot B's orders _are_ to follow pilot A. Back to our rollercoaster: by sitting behind an object (the first car), but looking at a separate "track" object (the second car), you can reproduce that "bob and weave" effect. Here's how to do it in Imagine. 1) In Action, set your Max. number of frames to 34. Save changes. 2) Go to Stage, frame 1. Create a suitable path: start off with a default Open path, and drag one of the points a bit towards +X and -Z. Save the path as "path". 3) Load a simple object; this will be our "first rollercoaster car". I used a simple elongated box for test purposes. The object's axis should be in its center, and the box should be roughly 5 times as long in (local) Y as in (local) X and (local) Z. This will ensure the object's shape conforms to the line of motion. 4) Add a couple of lights. You way want to add a checkerboard ground, to make the movement easier to see. Finally, Add an Axis. (Object menu) 5) Save changes, then go to Action. 6) To make things clearer, rename "axis" to "track". 7) To arrange our 3 objects along a path like the rollercoaster cars, we have to offset them in time. If you picture the cars in motion, the first one might pass a [ MORE ]

[ continuation ] certain point at 10:00:00, the second one at 10:00:02, and the third one at 10:00:04. They follow the same course in space, but they're offset by 2 seconds. In this case, we'll offset our object timelines by 2 frames each. Our goal will be to make the box (first car) follow the path from frames 1 to 30. We'll make the "track" or viewpoint (second car) follow the same path, but from frames 3 to 32. This is 2 frames later. Finally, we'll make the camera (last car) follow the same path from frames 5 to 34. In addition, we'll force the camera to "look at" our track object. Let's get to work. 8) First car: to make the box follow the path, click on the Delete button at the bottom, then click on the box's Position bar. Then click on the Add button, and click on frames 1 and 30 in the Position bar. Select "follow path". Enter "path" as the path name. 9) Second car: the Position bar at frame 1 doesn't get in our way like the box's Position bar, so we'll leave it alone. (No need to delete the current position) Just click on the Add button, then click on frames 3 and 32 in "track's" Position bar, select "follow path" and enter "path" as the path name. 10) Last car: again, there's no need to delete the camera's Position bar at frame 1; just add another bar from frame 5 to 34, select "follow path" and enter "path" as the path name. Then add an Align bar for the camera at frames 5 to 34, select "track to object", and enter "track" as the object name. This way, our "third car" will look at the "second car". 11) Save changes. You're all set to animate! The frames to render are *** frames 5 to 30 ***. These are the frames where everything is in place and moving; before frame 5, the camera isn't in place; and after frame 30, the box has already reached the end of the frame. This situation, where you create more frames than you'll actually use in your animation, is very common. For example, if you create 30 frames of animation with a moon following a closed path around a planet, the moon will be in the same [ MORE ]

[ continuation ] spot in frames 1 and 30; this will lead to a "hiccup" when the looping animation is played back. The proper technique is to create a 31-frame scene, but only render frames 1-30. (If you think about it, this is logical: when playing a looping animation, after frame 30 comes frame 1; therefore in the Stage editor, the object should be in the same spot on frames 1 and 31) There you are, a complex camera path with realistic tracking. You can adjust the frame offset between objects to make the camera track the box closer or looser. Enjoy! Blaq!

Mike, in addition to my last message, which dealt with placing objects and camera on a path, here's some insight into multiple circuits. The way I do multiple circuits is to make the path loop back on itself, like a tightly compressed spring. For example, create an open path and give it 9 points by repeadtedly selecting "split segment". Then use the following Position/Alignment coordinates: points Pos. Align ——- ———— ——– 1, 5, 9 100, 0, 0 0, 0, 0 2, 6 0, 100, 0 0, 0, 90 3, 7 -100, 0, 0 0, 0,180 4, 8 0, -100, 0 0, 0,270 I find it easier to use RightAmiga-N to select the next point when they start piling on top of each other. The result will be a double loop, which you can use to set up a single-loop animation with the object and camera offset from each other. Blaq!