Some advice on (shooting for) camera tracking?

[Snakedogman]

Hey people, I've got a request from an ad company to work on a video that would involve putting an animated cartoon bird into some real life footage they are going to shoot (of several locations inside a hotel).
It's been years since I've done any camera tracking and have never used the new built in camera tracker in AE. I've been watching some videos and tutorials on it's use and it looks like it gets good results quite easily from footage, even without any markers.

Do I need to tell the ad company to shoot with markers in their scene or is it unnecesary now? I guess if you had a greenscreen with no perspective info you would still be needing markers, but otherwise?

They sent me this as a reference although I don't think they'll be doing long tracking shots like that:

Obvion Commercial Bestaande klanten hebben een streepje voor (2013) - YouTube

[Szalam]

It really depends on the scene. In general, yes, you don't need markers if you're not in a flat environment, but it really depends. I can only suggest trying some test shots yourself and you'll start learning the pitfalls pretty quickly.

[kirkeric]

If that example shot is what they are kind of going for, I'd agree with Szalam, no markers needed, not to mention you'd then have to remove the markers.

There is some decent camera movement in that example, but it is smooth which helps.  The AE tracker works amazingly well though.

The key is having many features to track. Again, in the example video, there's tons to track so I'd say, have good lighting, steady and smooth movement preferred, no track markers.  Then use the AE tracker and I think it will do quite well.

Since I had some time, I did a quick test for you.  I literally, shot this, did the tracking and rendered in less than 15 minutes with pretty darn good results.

Let me know if this helps. The screenshot shows the how the tracker looks with one target and the finished product at the link.

https://youtu.be/wYQL94lCsRA​

PS:  I suppose it goes without saying that I added the little stick figure guys.

Eric

[Rick Gerard]

Unless there is absolutely no detail in the shot for the tracker to look for you do not need trackers.

Most important - shoot with lenses that do not have significant lens distortion. If you must shoot with a wide angle lens then you should shoot some test footage utilizing a grid and known geometry so you can create lens profiles to correct the distortion before you try and use Camera Tracking. AE's camera has no distortion so wide angle lenses can often be problematic.

If they put anything in the shot that is moving, like people walking through the scene, keep it simple so you can either roto them out or easily remove the trackers.

[Snakedogman]

Thanks a lot everyone. I will have a meeting with the production agency tomorrow where we will go over some storyboards. I feel more confident now

[Snakedogman]

Ok so they sent me this shot for testing purposes but I'm already having trouble with it. The camera tracker doesn't give me any solved points for the desk surface, which is not surprising since there are almost no discernible details, just a slab of grey. With the brick wall in your example it was a bit easier. I can put something on the back wall and it looks ok, but find it impossible to get something locked to the foreground surface.
Of course I don't know if the actual footage will feature completely detail-less surfaces like this or not but I guess in this case some kind of markers on the desk would be needed right?

[kirkeric]

Hello, just took a quick peek. I'm guessing the two people in the scene are causing errors.

You'll want to mask them out so that the tracker doesn't see them.

If nobody gets to this, I will attempt a track tonight and see if I can help ya.

Eric

[Snakedogman]

Thanks, does it help if you delete the tracker points AE generates on the persons?

I've done some more testing and changing the solve method to "typical" gave me a bit more usable results. I've managed to put some elements on the surface and, while not perfectly locked, it may be satisfactory for the purposes of this production.

I'm gonna spend some more time on it as well tonight. Thanks for the help!

[kirkeric]

That's a reasonable question to ask. Logically you would just not use those if that were the case. But no, the moving people actually do interfere with the track so you want to exclude them in the track for best results.

Good to hear that you were able to get some fair results.  There is also the mask tracker which would probably work well on this.

Here's a tutorial for that.  What it's kind of missing is you would want to parent your object you want to place on there with the tracked mask as shown in this tutorial:  https://youtu.be/Ylvg5IOZrQg

There is also a little plugin that works well in conjunction with this Mask Tracker.  I think it's free.  Mask Tracker plus I believe.  It basically let's you track using the AE Mask Tracker, then easily assigns that data to your object.

Eric

[Szalam]

Rather than markers, it would be better to just sit props on there that make sense for the scene. That way you don't have to paint anything out. The tracker needs SOME detail, but it would be better if it were details that you didn't have to remove later!

Also, yes, masking out other movement helps a lot on any shot!

Mask Tracker Plus is $50

You also might look into using Mocha AE (comes free with AE). You can often get great results with a 2d track too, depending on your shot.

[Snakedogman]

Thanks again, I had the same idea about the props. In this case I can just about use the trackpoints on those bell things and the glass as a "base" for putting objects on the surface, and the camera itselfs solves ok with 2.2 pixels error. I've deleted all the trackpoints on the people moving so they should not influence the solve anymore (I think). It's not perfect but I think it's good enough for now.

I can try having a look at Mocha. It always looks so intimidating to me though

Do you have any experience with the tracker in Cinema 4D? Does it have any advantages over the AE tracker? I could also use that although for this project it would make more sense to stay in AE as we don't need any true 3D geometry, just flat characters.

[Kevin-Monahan]

Hi Snakedogman,

Were you able to solve your tracking issue? Did the advice you got here help you solve the issue? Please let us know by marking that answer as the correct one. I noticed that no one responded to your last missive. Do you still need help, perhaps?

Thanks,
Kevin

[Snakedogman]

The advice did help, though I wasn't really having one specific issue so can't really mark one answer as the "correct" answer. All the replies were helpful. I managed to complete the project succesfully and learned a bunch about using the tracker. Often I precomped the footage to be tracked and masked out any people moving in/through the frame, then I could get a decent enough track. Some shots were hard because the featured many reflections or little trackable details, but in the end I think the results were good enough.