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Posted on 22/02/07 6:40:17 PM |
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GKB
Magical Montagist Posts: 4033 Reply  |
Compositing problem
I’m currently putting together a time-lapse film of my home village of Ditchling, in Sussex. One of the sequences is to be the old chestnut of the moon rising behind the silhouette of a tree. The moon will be shot full frame. I have shot this already using a time lapse sequence of the full moon and then compositing it together with the tree in Premiere Pro. It has to be a composite shot because of the uncertainty of knowing exactly where the moon will rise in relation to the tree. Does anyone know how I could take a single frame of the moon and composite it with the tree shot for around 300 – 400 frames with the tree stationary but the moon moving, say, 2 pixels up and 2 pixels right after every shot? I expect that the answer lies in ‘Actions’ but I can’t figure out how to automatically create 300+ copies of the same tree image in a folder and then drop the moon in and move it a little more with every frame. |
Posted on 22/02/07 8:31:03 PM |
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dave.cox
Marquee Master Posts: 518 Reply  |
Re: Compositing problem
I don't know Premiere Pro, but does it support Javascript as in Photoshop? Seems like it would be fairly easy process using javascript. ie: for ( i = 0; i < 600; i++) { do next drawing } ; If not in Premiere Pro, perhaps with image ready. |
Posted on 23/02/07 04:04:31 AM |
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Bob
Expert Expressionist Posts: 130 Reply  |
Re: Compositing problem
I have Premiere Elements not Premiere Pro, but the technique is similar. Use keyframes. Place the tree clip on one track, place the still on a second track and stretch it to the desired length. Select the moon clip and position the cti to the start of the clip and set the position of the moon to the starting position in the frame. Create a keyframe for position. Move the cti to the end of the clip and create another keyframe. Set the position to the ending location of the moon in the frame. If you haven't already, set the spatial interpolation to Bezier for both keyframes. Adjust the handles for the two endpoints of the path until you get the curve you want -- just like you would using the Photoshop pen tool. You've now defined the path the moon will travel through the clip. If you want, you can adjust the temporal interpolation to control the rate of rising and you can use keyframes on the scale to vary the size of the moon as it rises. You probably don't need to do either of these though. Have fun. Edit: The default is a straight line from beginning to end position. If you just want a straight line motion for the moon, you don't need to fiddle with the interpolation method. I also forgot to mention that since the moon will be behind the tree, you'll need to a use some kind of keying or matte to control the transparency. Possibly you can use a track matte for this. Pro and Elements work a bit differently in the number of options and how you specify them. I can't help you there, you'll need to experiment. I'm sure you can get something that will be satisfactory. If the tree branches aren't moving you might be able to do a frame grab and make a still matte that can be used in conjunction with track matte. |
Posted on 23/02/07 05:58:25 AM |
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Bob
Expert Expressionist Posts: 130 Reply |
Re: Compositing problem
Gordon, I just had a thought. Why not upload the frame of the moon and a frame of the tree (heck, 400 frames isn't that much, you could even export them as a DV-AVI and upload that) so I can see what you are up against. |
Posted on 23/02/07 08:36:19 AM |
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GKB
Magical Montagist Posts: 4033 Reply |
Re: Compositing problem
Thanks Dave and Bob, I have to admit that I figured Javascript might rear it's head on this one but as someone who considers Javascript to be a bit of 'White Man's magic' I may not be able to go down that route at the moment - however it might be a good place to start learning! Bob, I hadn't though of using keyframes but your method sounds like it may well work, especially as I shall, essentially, be using two still images and the tree already has a matte. I won't be doing this for a little while yet as I have too many things going on right now but I'll let you know. Gordon |
Posted on 23/02/07 09:38:59 AM |
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Steve Caplin
Administrator Posts: 7052 Reply  |
Re: Compositing problem
I don't think Actions will work here, Gordon: surely the moon has to move in an arc, rather than a straight line? Your best bet is Adobe After Effects, which is like Photoshop with animation. You could draw a path here, and have the moon automatically follow it. Since AE can import Photoshop documents, you can create the entire animation in Photoshop and then go into AE to make it move. Pricey, though! |
Posted on 23/02/07 2:43:18 PM |
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GKB
Magical Montagist Posts: 4033 Reply |
Re: Compositing problem
Thanks Steve, Yes I realised that the moon would follow an arc but due to the extreme magnification it would hardly be noticeable as the radius of the arc would be so large. An interesting solution though. I'll see if I can make it work. |
Posted on 23/02/07 9:20:38 PM |
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Bob
Expert Expressionist Posts: 130 Reply |
Re: Compositing problem
I can do this easily using just Premiere Elements and keyframes -- including the curved path. Doesn't Premiere Pro have this level of keyframe support or is After Effects necessary to do this with Pro? Just curious. |
Posted on 23/02/07 9:35:01 PM |
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GKB
Magical Montagist Posts: 4033 Reply |
Re: Compositing problem
Hi Bob, Yes, checking through Premiere Pro it does have that function so it looks as though that is probably the way to go. I've never used this function before but I can't see that it will be a problem. The original question was posed because I had become focussed on how this could be done in Photoshop to the exclusion of other programmes. In fact it now sounds so easy to do in Premiere that I'll forget all about Photoshop and After Effects for this one. ttfn Gordon |
Posted on 23/02/07 9:59:13 PM |
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Steve Caplin
Administrator Posts: 7052 Reply |
Re: Compositing problem
I love this forum. So much talent and expertise! |
Posted on 25/02/07 12:46:48 PM |
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GKB
Magical Montagist Posts: 4033 Reply |
Re: Compositing problem
Bob, I've just tried a test run of keyframes in Premiere with a moon rising from bottom left to top right and it works beautifully. I achieved in 5 minutes what would have taken me hours in Photoshop creating all those individual images and then rendering them in Premiere. It was a dawdle to do. It just shows what happens when you get fixated on one idea to the exclusion of others. Thanks for your help on that one. Gordon |
Posted on 26/02/07 10:07:55 AM |
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Bob
Expert Expressionist Posts: 130 Reply |
Re: Compositing problem
That sounds great! Glad I could help. |