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View Full Version : How do I use 3d track data in LW?



Algae998
08-18-2007, 08:07 AM
Hello all!
This is my first post, and so far Ive gotten some much needed info from this forum. Although I have searched for this particular question, I didnt get any results, so here it goes...

I would like to know how to use/setup the 3d tracking data from a tracking app (boujou, syntheyes, etc..) in Lightwave v9. Is there an "easy" or simplifyed way or am I jumping into water without a life-jacket? I kind of just began using Lightwave and my ultimate goal is to use my model with 3d tracking.
I realize I might be looking a bit down the road but I do have a bit of experience with the 3d trackers (experimented in After Effects). Is it anything like this? Do you have to have the animation of the model 100% complete, then toss it in with the filmed footage or do you animate the model based on the footage?

If anyone knows of a website/forum that I might have overlooked in the past couple weeks of researching this, posting it would be a big help. Like I said, I am a beginner at this but its something Ive always wanted to do and Im siked! I cant wait another semester or two to learn this in school...I want to learn it now! haha.
Any help or insight would be extremely appreciated!!!!
Thanks in advance
-Aaron

Sekhar
08-18-2007, 08:49 AM
I'd get the book Matchmoving: The Invisible Art of Camera Tracking (http://www.amazon.com/Matchmoving-Invisible-Art-Camera-Tracking/dp/0782144039). I have it, and I can tell you it's a good resource for getting started.

Matchmoving apps export the cameara data in LW scene file, so that part (of getting the 3D data into LW) itself is trivial. I've just finished a short film with MatchMover and LW, and the hard part for me was really on the matchmoving (tracking/solving) side. Scene fitting (making your LW scene fit the imported camera) can also be tricky if there's close interaction of the live footage with the CG objects.

Algae998
08-18-2007, 09:03 AM
Yea, I figured itd be difficult to get the data working correctly. Like I said, Im just looking down the road and want to know how to do it by the time I get there. My scene that I want (to start off) is to just have my modeled tank roll across my computer desk, which Ive 3d tracked the desk. I just wasnt too sure how you use that data in LW or if it were very difficult to use. I saw a video tutorial on youtube where the narrator was using Boujou then exporting to 3ds Max, where the track data was a script. Thats where I became lost, since I come from After Effects I wasnt up to par on scripts and such. Will it be similar in LW where you need to setup/edit scripts or is it more of a "plug and play"?

Thanks for the heads up on the book, Ill have to check it out!

-Aaron

Algae998
08-18-2007, 10:50 AM
Just as an update: I checked out that book and it looks great; very informative for getting the scope of things. Hopefully once I get it Ill have a better understanding of what Ive gotten myself into:D .
But in the mean time if anyone has any other information they can lend a beginner, thatd be great!
-Aaron

lwlurker
08-19-2007, 01:22 AM
Oliver, what do you do if you need to smooth the motion out upon export? I'm learning PFTrack, and the instructor is using 3DStudio to do the 3D part with. So he smooths the motion curves there. Unfortunately, I can't find a way for Lightwave to smooth out curves in the graph editor (and the keyframe reduction option makes things worse, since it only eliminates those frames that are most alike, leaving the "rebel" keys with even more influence. I can't find a way to smooth motions in PFTrack directly.
Any thoughts would be most welcome.

lwlurker
08-19-2007, 01:33 PM
The particular instance I was dealing with was a man walking across a lawn. He's carrying a suitcase in the hand opposite the camera. The camera is handheld, and walking beside him. The goal was to track down the 3D geometry of the ground, and then object track the mostly-hidden suitcase up until he puts it on the ground. From there, it is to remain immobile on the ground while the camera continues to move.
It's a tough shot, and a lot of the "noise" in the motion tracks are with the geometry track of the suitcase. The actual motion isn't high-frequency, but PFTrack's solution has a lot of noise because of the situation -- standard-def interlaced video trying to establish transport and rotation of a mostly hidden object :)
So, yes, the instructor smoothed out the oberrations quite easily in 3DSMax, and the match was quite good. I'd forgotten if Lightwave had the ability to mathematically effect its own graphs. It's a shame if it doesn't, since mathematical expressions should be able to influence anything in a computer program! Even Aura could let you average tracks, or something.

Thanks for your input, though. Nice to see someone's having good luck with this workflow :)

Lurker

Sekhar
08-19-2007, 01:50 PM
I use MatchMover, so can't comment specifically on PFTrack; but as a general matchmoving principle, you should not include the tracks of the moving suitcase (or of any moving object, really) for solving the camera. Exclude those, and you should get a smoother solution. You can of course include the suitcase tracks after the thing becomes stationary on the ground.

I know this isn't useful to you; but for others considering MatchMover, it lets you smooth out the curves in a variety of ways. Works great too.

lwlurker
08-19-2007, 11:47 PM
To clarify, I have a very smooth camera solution. It's the suitcase's motion that has so much "noise" in it. And while PFTrack allows smoothing motion within the application, those "smoothed" moves have to be recalculated in with the original data, which I don't know how to do (yet).
Do you think an expression could be written to smooth a channel? Seems like it should be possible maybe? Copy the trouble channel to a new one and then do something to it?
I'm surprised I can't find any googled topics for it.
I'll keep looking.
Lurker

archijam
08-20-2007, 01:29 AM
Also, check out Icarus, it's free (non-commercial) and there's lots of info on the net ...

http://www.peerlessproductions.com/tuts/pages/Icarus.html

(this is just a tutes page)

j.