View Full Version : 3D Tracking
02 February 2003, 10:37 PM
We're working on a Feature Film (shot in HDTV 1920x1080_24p) that will need to use a 3D Tracking solution.
We'll be using Inferno 4.0.3 for visual effects and 3ds max for 3D.
The opening will consist on a actor who will be singing and walking thur different streets in a virtual city.
The actor will be shot on a Greenscreen studio and the virtual city will be created in 3D.
So we'll need to match the camera movements made while shooting the actor in the Studio with the camera in 3Ds max and with the camera in Inferno.
This opening will have a duration of 2 minutes.
Could anyone give me some recomendations (tips and tricks) on:
- what software would be better for this? Realviz, Boujou, Equalizer or use the Inferno 3D tracker.
- how to mark the greenscreen in the studio. Put marks on the wall, floor and additional objects in the studio that would help the 3d tracking.
Any info. is appreciated since this is the first time we'll be doing this type of work.
02 February 2003, 02:45 AM
SceneGenie! It works within max and I've had some amazing results with it. One of the first shots that we tried with it was a free move with a zoom. Boujou can't even do a freemove with a zoom. I had it done with SceneGenie within 30 minutes. The 2d3 people never got it to work. For SceneGenie to track you need at least 6 tracked points.
You can read more about it here (http://www.scenegenie.com)
02 February 2003, 09:25 AM
Yes boujou has that problem a little.
Realviz could workout ok for you and the tracker in inferno ins't to bad to.
for what about the marks for tracking I normaly use a bluescreen and place green crosses on the bluescreen you can later take the blue and the green out with a keyer like ultimatte.
I normarly place 1 crosse in 1 m2 for the best tracking result.
hope this helps,
02 February 2003, 10:36 AM
3dsmax has a 3d matching/matchmoving capability. I havent tried other apps but Realviz Matchmover is good (according to our sister company). Import your data to Inferno or Max. Max can fairly do the tracking/matchmoving alone. I haven't tried the Inferno 3d tracker though ('coz small machines/apps are assigned to this purpose).
Regarding the tracker marks, I suggest you place them on the areas where it doesn't visually overlap with the talent. You can safely place then on areas where he wouldn't step on them when he/she acts 'coz this would be a problem during keying. I suggets that you use a color (tracker marks) that is lighter with the chroma cloth so you can easily key them out in inferno or (shrink the matte). Light blue tracker marks for blue screen and light green for green screen.
I hope this helps. :cool:
02 February 2003, 10:40 AM
Making on site measurements of the tracker's relative distances to each other and to the camera lens is also valuable to the 3d artists.
02 February 2003, 08:45 PM
Thanks alot for your useful help guys.
02 February 2003, 06:26 PM
I would check out icarus. It's a really nice tool and has many additional features that are pretty nice(some mokey/pixeldust like features). The best thing is that the developers are always answering questions and are very open to suggestions and will add minor requested features(if resonable) in the next point release(they have new point releases every 2-4 weeks). It comes very close to rivaling features in boujou but at 1/10th the cost.
02 February 2003, 07:59 PM
I wouldnt recommend the MAX-own tracker though, it works but its tricky.
What i found very important is to make sure to not have lots of trackers only in an area lets say on the back-wall, they dont help - what really helps the app is having trackers very spread in space, say foreground to background so they have maximum persp. movement one to another.
02 February 2003, 10:07 AM
If you shoot in green make the markers in blue and vice versa, this way you can key them out with no problem.
On site measurements is always a good idea, and may solve a lot of problems of scale etc...
Fewers markers can generate some errors in the tracking, making the tracking less precise and more dificult to do, so do some simulation of the camera movement and see what is the ideal space between the markers.
Boujou can achieve some honest results but he have some limitations, Icarus is awsome and it's free for personal use.
3D Equalizer for all that I have reseached is the most powerfull of all, but is kinda tricky to set up, but the results we all already seen in major motion pictures like Lord of The Rings, Babe 2, Entre las Piernas and many others, so I don't need to speak.
Bom seria bem mais facil se eu pudesse falar com voce em Portugues, entao se vc se interessar me manda uma PM, adoraria lhe ajudar se e que eu posso. E me desculpa pela falta de ascentos mas nao esta rolando aqui.
02 February 2003, 11:06 PM
Thanks alot for the info.
We shot the opening today and hopefully all of the markers will work fine.
I┤ll try to send a frame of the Studio later so you guys can see how we marked the Studio.
Obrigado pelas dicas.
Vou enviar um PM mais tarde para que posamos conversar.
02 February 2003, 03:42 PM
'Tis a bit late since you've already shot, but I'll say it anyway:
Place markers where he's going to walk!! Maybe not so he steps ON them, but maybe so they're in two rows, to the right and left of his path, respectively.
It's true what wireFrame says, that if they overlap with the actor, you'll have to mask them out, and that can be troublesome (unless you can key them out, like diogo said), but I'll say this:
Manually masking out tracking markers is IMHO A LOT easier than manually fixing a bad tracking.
If your actor is totally greenscreened, walking in a total CG environment, THE NUMBER ONE TRACKING PRIORITY is to track the plane he's walking on. That's a billion times more important than anything else. (But of course, yes, you'll also want markers on the back wall, preferably in a grid of perfectly horisontal and vertical lines, just to get the orientation of the entire scene.)
Bottomline is, the background tracking may be a bit off, and people won't notice, but the slightest, tiniest little fault in tracking the floor will make your actor slide on the ground, and that's BAD.
This is, of course, all under the assumption that you have shots where his feet are in frame. ;)
01 January 2006, 09:00 AM
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