-
Make something fly against screen / viewpoint
Hi all.
Lately have been playing around with some stuff in AE and have found a problem. I am trying to create a sequence where a smoke like object gets thrown against the screen / viewpoint. I am working on a 1280 by 720 comp. I though that I could just have the object move from x640 y360 z0 to something like x640 y360 z-1000 or something and I’d get the effect, but no. I actually figured out it’s closer to -1600/-1700. The issue isn’t the value, it’s that the closer the object gets, the object starts to veer off course and always ends up looking like it’s going to pass left or right of the viewpoint and never quite dead center. So my question is, how can I determine the exact coordinates for the center of my current viewpoint?
-
4 Replies
-
The center of your screen is always half the horizontal and half the vertical resolution of the composition. So [640,360] is the center of a [1280,720] composition.
With 3D layers, the closer your layer gets to the camera the more any offsets from the center of the screen will be magnified. If you imagine a 3D grid of pixels, instead of the usual 2D grid of pixels, the pixels get larger as you get closer to the camera and smaller as you get farther away. This amplifies any offset from the center of the composition.
Also remember that the position property defines the position of your layer’s anchor point in the composition. So make sure that your anchor point is on the part of the layer that you want to occupy the center of the screen.
Darby Edelen
-
Thanks for that explanation. As I am just getting my feet wet in AE, that was pretty helpful. I am currently working on a simple project file. I haven’t created any camera yet. I also haven’t changed any position values other than those of the effects I am running. That said, I expected the center to be the 640 – 360. I just don’t know what value in Z it would take to have my object “touch” the viewport. Anyway, I’ll keep trying since so far I still haven’t gotten the effect to hit me on dead center.
-
[Nuno Marques] “I just don’t know what value in Z it would take to have my object “touch” the viewport. Anyway, I’ll keep trying since so far I still haven’t gotten the effect to hit me on dead center.”
You get to decide how close is close enough. If someone were making this a practical effect then they would likely set up a glass or plastic sheet at an arbitrary distance for the object to hit. Depending on the size of the object you may want this arbitrary distance to be larger or smaller.
This relationship is easier to understand if you have a camera layer in your composition.
Darby Edelen
-
Thanks. I’ll take a deeper look into camera and camera layers. Meanwhile that plastic solution was what I went with and it worked pretty well.
Reply to this Discussion! Login or Sign Up