Perspective Motion Tracking

[Dysania]

A couple months back I was working on a PSA. We came up with a good idea but we found out we were really way in over our heads cuz we're only in gr 11. Anyway i spent hours and hours looking at tutorials and reading a bunch of books but we still haven't finished this project. yet.

So everything was going good until i started motion tracking some footage. This is sort of the effect we were going for. Except in our case we have a family tree where each name has a video of the person in it. sort of like Harry Potter where all the portraits are moving. ===>http://www.youtube.com/watch?v=ItjNnzEhMC0

The question i have is how do you keep the footage in perspective as its going off the screen. It gave me huge headaches trying to figure it out and please dont tell me its all manual work. Also as I tried to analyze the footage some points were jumping around everywhere because all they had to analyze was the grey outside the comp window...

Is this the right way to do it anyway? Is there an easier way to achieve the effect in that music video?

 

[Matt Grunau]

It's manual work. :grin:


Seriously though, simply erase the track data keyframes from your corner pin as the layer goes offscreen, and manually set your keys. You shouldn't have that many frames to worry about, and if you do or if that is too tedious, have your camera operator keep everything on screen. Or, have the movements be a constant pan or dolly through the shot, as that will help approximate where it should be.

You'll probably have to set a few by hand though. It's good, it'll keep you humble.

 

[SomewhereinLA]

I am not sure I understand, but did you actually shoot the familly tree, the camera is moving from one branch to another and you are trying to motion track the people?

 

[Matt Grunau]

I am not sure I understand, but did you actually shoot the familly tree, the camera is moving from one branch to another and you are trying to motion track the people?

That's what I thought he meant, but you are right: If the tree was a large graphic element, there's no reason to track. He could just put all the videos in their proper place and set up a new comp for NTSC and have the tree comp move around in it.

 

[Dysania]

Seriously though, simply erase the track data keyframes from your corner pin as the layer goes offscreen, and manually set your keys.

Is there a way to stop one track point from analyzing so i could move it manually?
thanks

I am not sure I understand, but did you actually shoot the familly tree, the camera is moving from one branch to another and you are trying to motion track the people?

sorry if i didn't make any sense, I wish I had the video of the "tree" that we animated to explain it better. We made it in 3ds max and it is a family tree on a piece of parchment and the camera does a fly by. It is not an actual 3d tree, its a piece of paper where there is a video portrait above each persons name (about 20). If you clicked on the link of the music video that is almost exactly the same effect that we were trying to achieve. Hopefully that made some sense.

 

[SomewhereinLA]

That's what I thought he meant, but you are right: If the tree was a large graphic element, there's no reason to track. He could just put all the videos in their proper place and set up a new comp for NTSC and have the tree comp move around in it.

Exactly, his entire workflow is wrong...

Matt,

what you need to do is create a hi res file of your tree, bring it in a compositing software such as after fx along with the people, place them as they should on your tree, parent them to the tree and move the map using keyframes. If you want 3d perspective then turn 3d on and use after fx camera.

This is basicaly how it should be done...

 

[Dysania]

hmm... I think i sort of understand what you mean but I don't know what parenting is and also I don't know how to keep the 3d info of the 3ds file. Or should i redo the tree inside AE? forgot to mention im a complete newb at all this

also how high would hi res be. I exported it as HD, is that not enough?

 

[Matt Grunau]

Is there a way to stop one track point from analyzing so i could move it manually?
thanks

Sure, just select the keyframes applied to your layer after it begins to move off screen and delete them. Then track by hand. This is if you had video footage.

I wish I had the video of the "tree" that we animated to explain it better. We made it in 3ds max and it is a family tree on a piece of parchment and the camera does a fly by. It is not an actual 3d tree, its a piece of paper where there is a video portrait above each persons name (about 20).

If you are rendering from 3D max, the best way to do it would be to use the video files you are trying to composite in and use them as textures in 3d Max. That way, you would render the video straight out of your 3D app, and wouldn't need to fuss with AE at all.

For added flexibility, and since you are rendering from a 3D app, you can also render the video textured portions seperately, and the camera movement will be identicle. This allows you to composite them in however you want in AE, simply using masks to decide what you see and when.

also how high would hi res be. I exported it as HD, is that not enough?

The size of your render depends solely on the amount of movement and size of the tree respectful to the frame size in NTSC. I would say that HD is not nearly big enough. If I had to render something to be panned around in AE, I would make it at least five times the size of my AE comp, and maybe more. The files will be huge, but you will also have the advantage of being able to zoom as well as adjust position.

Or do what SomewhereinLA suggested in his last post with the 3D layers. All of those options are easier than trying to motion track it.

Using you video as textures inside you 3D app would be the way I would do it.

 

[Dysania]

wow thanks a lot. All I have to do now is find some more tutorials in 3ds max... oh well.

Hopefully I'll get to post the video on here when it's done. if.

Thanks