Tracking a 3d flyby on moving 2d footage?

A place for beginners to start

Tracking a 3d flyby on moving 2d footage?

Postby Opiateofthemasses on 03/6/2015, 3:36 am

Hey guys, so I've been messing around with making my own "destroyed city" comp, using a lot of the methods from the video copilot tutorial. I have a pretty good understanding of the basics when it comes to, say, tracking the damage onto the buildings (it was really well explained lol) but I am having an issue with tracking an element 3d object from one side of the screen to the other, but also maintaining its proper position (or altitude in this case) in relation to the video movement, which is slowly rising over the city. I am just wondering what sort of tracking I should use for this?


I attached an mp4 of the 10 second clip I'm using. I am wanting an object, like a plane or spaceship, to fly from the out of frame right, to the out of frame left, between my smoking building in the middle ground, and my damaged building in the foreground and it will be high enough that no masking should be required. I just can't for the life of me remember how to do this properly using after effects and element. Thanks guys :)
Attachments

[ Play Quicktime file ] Sequence 01.mp4 [ 4.08 MiB | Viewed 3015 times ]

Opiateofthemasses
 
Posts: 6
Joined: 02/27/2015, 4:47 pm

Re: Tracking a 3d flyby on moving 2d footage?

Postby ctarv419 on 03/6/2015, 2:52 pm

Is this real footage of a city or something created with Metropolitan or another 3D program? I don't know why but I just can't shake the feeling that those buildings don't look quite real. If its CG and you have the scene file obviously you wouldn't be asking on this forum, so I would say whether it's real or computer generated, the first thing you need to do is get a good 3D track of the scene and create a Camera with the solved 3D data. I'm pretty sure AK does that in the beginning of that tutorial, he doesn't use the camera data a whole lot but I think he did it because I remember later on he uses 3D planes to mask out the buildings in the foreground which probably uses the 3D camera. I'd go watch it again to make sure but I can't right now because I'm at work. Even if he doesn't solve for the camera, once you have the track, pretty much all you have to do is click Create Camera. I'm sure there's a VC tutorial for it somewhere. Once you have the camera created, just create a new black solid and apply E3D, and put your model into the scene like normal. It will automatically use the camera you created, which (if you had a good track) will match your footage pretty close to perfectly. Once your spaceship is in real 3D space you can scrub through the footage and see about where it is, and about what size it is. You can create a group null from the E3D effect in the Effect Controls panel, and move/scale that null to adjust the size and location of your spaceship. Once you get the right size and general location, all you have to do is move it to its starting point and set a keyframe, then move it to its ending point and set a keyframe. Again, it's a lot easier if you use the group null. You can also create lights to make it match the look of the scene, and tweak your settings like depth of field and motion blur to really anchor it into the scene.

Hope this helps... I'm bored at work which means I can think through it in my head but I can't actually get on After Effects and play with it.
I really miss being able to have an Avatar : (
ctarv419
 
Posts: 97
Joined: 02/1/2014, 10:25 pm
Location: Lake Charles, Louisiana USA
Twitter: ctarv419
System Specs: Build: Element x64 2.2.2 (2160.hotfix)

OS: Microsoft Windows 10 Pro 64-bit 10.0.17134

CPU: AMD Ryzen Threadripper 1950X 16-Core Processor
RAM: 65410MB

GPU Vendor: NVIDIA Corporation
GPU: TITAN Xp/PCIe/SSE2
GPU Driver: 24.21.13.9836
GPU RAM: 12288MB
GPU Code: 0

CL0: TITAN Xp (100.0%) (GL Interop)

Re: Tracking a 3d flyby on moving 2d footage?

Postby stayhigh on 03/6/2015, 3:33 pm

Cant you just use null objects and copy paste the position? You 3d track the footage choose a null where you want to place your 3d object, then use the element option that generates a null object as a controller and paste the position there
stayhigh
 
Posts: 226
Joined: 12/15/2010, 6:36 am

Re: Tracking a 3d flyby on moving 2d footage?

Postby Opiateofthemasses on 03/7/2015, 3:00 pm

ctarv419 wrote:Is this real footage of a city or something created with Metropolitan or another 3D program? I don't know why but I just can't shake the feeling that those buildings don't look quite real. If its CG and you have the scene file obviously you wouldn't be asking on this forum, so I would say whether it's real or computer generated, the first thing you need to do is get a good 3D track of the scene and create a Camera with the solved 3D data. I'm pretty sure AK does that in the beginning of that tutorial, he doesn't use the camera data a whole lot but I think he did it because I remember later on he uses 3D planes to mask out the buildings in the foreground which probably uses the 3D camera. I'd go watch it again to make sure but I can't right now because I'm at work. Even if he doesn't solve for the camera, once you have the track, pretty much all you have to do is click Create Camera. I'm sure there's a VC tutorial for it somewhere. Once you have the camera created, just create a new black solid and apply E3D, and put your model into the scene like normal. It will automatically use the camera you created, which (if you had a good track) will match your footage pretty close to perfectly. Once your spaceship is in real 3D space you can scrub through the footage and see about where it is, and about what size it is. You can create a group null from the E3D effect in the Effect Controls panel, and move/scale that null to adjust the size and location of your spaceship. Once you get the right size and general location, all you have to do is move it to its starting point and set a keyframe, then move it to its ending point and set a keyframe. Again, it's a lot easier if you use the group null. You can also create lights to make it match the look of the scene, and tweak your settings like depth of field and motion blur to really anchor it into the scene.

Hope this helps... I'm bored at work which means I can think through it in my head but I can't actually get on After Effects and play with it.


Haha thanks man. Yeah I got pretty much all that taken care of, I got the tracking data all set up and everything, the main problem was just getting it maintain altitude...maybe its a perspective thing? I don't have any tracking points in the sky obviously, and whenever I attach it to one on the ground, raise it up, and try to scrub through, the model just gets lower and lower as the live action footage camera rises...its kinda weird. I'm probably just going crazy lol. I'll try just nitpick keyframing it upwards every few frames... I might have even been dumb enough to not activate my keyframes in the first place lol...now I gotta check, thats more likely than this being so weird. BTW the footage is real Chicago :P
Opiateofthemasses
 
Posts: 6
Joined: 02/27/2015, 4:47 pm

Re: Tracking a 3d flyby on moving 2d footage?

Postby Opiateofthemasses on 03/7/2015, 3:19 pm

Derp...yeah so I didn't activate the keyframes lol.... I knew it had to be something dumb.
Opiateofthemasses
 
Posts: 6
Joined: 02/27/2015, 4:47 pm


Return to After Effects Fundamentals (Beginners)