Camera Tracker, Green Screen, and a 3D Room

[Sean Morton]

I used the foundry camera tracker plugin

[Shawn Miller]

Can you post an example of the clip? It’s possible that something in the shot is throwing the track off, or you might not have enough features to get a decent track…

Thanks,

Shawn

[Ben G unguren]

+1 to Shawn. We need to see what you are up against before giving very useful advice.

Ben Unguren
Motion Graphics & Editing
http://www.mostlydocumentary.com

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[Tudor “ted” jelescu]

Camera Tracker usually does a pretty good job in figuring out the camera move without a ground plane. You may need to play around with it and chance the settings to get it to give you a better track.
Also, if the camera goes around the actor, vanishing point may not be your better option (there are some weird issues when bringing that in AE- I think Andrew Kramer has a pretty good tutorial that explains how to fix that). I would create the pieces of the 3d room in PSD as separate planes and then build that space in AE with 3d layers.
I also agree that you may be able to get better feedback if you post something for us to see.

Tudor “Ted” Jelescu
Senior VFX Artist

[Sean Morton]

Yes i sure did find some weird issues. specifically with orientation and it took forever to get something working. I am trying to work out setting up orientation easy. Parenting a 3d object to one of nulls isn’t my problem. It’s getting proper perpsective in a 3d room without the perpendicular walls warping.

Where would you place your “origin” in your camera tracker plugin? I tried following the latest red giant piece to no avail. If i were to camera track/greenscreen and create scene with my footage, would it be wise to turn off all those layers (thereby not confusing me) and build the proper 3D room in AE with proper orientation. How would i then match the proper perspective of the camera movement that has already been created.

Any suggestions would be appreciated. I did look at the old Creative Cow video of Aharon Rab… on the problems with vanishing point. It was helpful to point them out and the solutions were helpful but still couldn’t fix my vanishing point footage… I will give up on that way of doing things.

Here is the Test Footage and what i intially tried to fix using vanishing point. I also felt that the orientation of the Null was very screwed up from camera tracker. i had to play with the null for hours to try to get the created camera to give me the same orientation as I originally shot. it isn’t finished but what i want to try to avoid is the warping of walls while panning.

https://youtu.be/z6zGTTw7q6E

Thanks for any help Crew!!

[Shawn Miller]

Hey Sean,

I think the problem is your footage. You don’t have enough features distributed throughout the shot. To fix this, you might try putting markers not only on the green screen, but also on some stands (with markers) randomly arranged in the shot. Remember, what the tracker is looking for is parallax shift… or the comparative difference in movement between identifiable features. So, if you have objects close to the camera and objects far away from the camera, the software will have an easier time solving the shot. You might also consider using bigger, smoother movements (like a longer dolly shot)… jerky camera movement can add a sense of realism, but it also makes it harder to get a solution with minimal errors. Lastly, make sure that your subject is omitted from the solution, unless your talent is DEAD STILL (and they never are), you should instruct your software to ignore trackers on people, or anything moving… unless you’re doing object tracking and camera tracking at the same time. I hope this all makes sense.

Thanks,

Shawn

[Shawn Miller]

Sorry, I meant to post an example. For this shot, I used features on the ground, on the house, on the dumpsters and on everything that isn’t moving. This made the track easy…

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Thanks,

Shawn

[Sean Morton]

I am going to try your suggestions next time. I don’t think that what I was trying to do is that unreasonable a shot to work with. (i.e. moving around the subject with some motion) My idea being to make it as realistic an enviornment as possible. The idea of placing additional tracking stands sounds reasonable. Maybe the parallax will be more authentic assuming that the closer trackers will move faster than the rear trackers. However if i am trying to move on axis around the actor those stands will get in the way of that movement.

Any other ideas anyone??

Sean

[Sean Morton]

I think a lot of my trouble was working without a ground plane which in that example you had a lot of.

I suppose i could shoot from further away but i wanted a closer shot and i don’t want to digitally zoom in so that I lose my resolution.

Anybody else??

[Shawn Miller]

“I think a lot of my trouble was working without a ground plane which in that example you had a lot of.”

You don’t necessarily need a ground plane, just enough (motion) information for the camera tracker to get a good solution. I think the biggest issue with your shot is that you’re trying to get a solve with one plane (behind the actor), and not very much motion. You might be surprised at how much easier one or two c-stands with markers on them can make you life.

Shawn