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realgray
01-17-2009, 06:00 PM
Hi all, had a question. I wanted to know if anyone has done limb replacement like in Pans Labyrinth or Planet Terror. I'm working on a zombie flick and need advice. This is my work flow so far. The actor is going to wear green screen socks to be removed. I am going to 3d track the scene (syntheyes), which will then be exported to Lightwave. Then I am going to model/animate/render the legs using Lightwave's compositing tools to line up the legs to the actor (sounds tedious). These legs are going to be transparent in certain areas as they have been severely decayed. I've seen fantastic work done by the artists on CSI but I'm building the effect on my own and I'm worried I may be missing something. Any thoughts? I'll post a some tests soon.
Thanks for any advice,
Gray

Mr Rid
01-19-2009, 07:31 PM
Sounds like you have the basic idea. Check my post here for a little trick on 'Matchmoving in Lightwave'
http://www.newtek.com/forums/showthread.php?p=809819#post809819.

jin choung
01-20-2009, 01:27 AM
Hi all, had a question. I wanted to know if anyone has done limb replacement like in Pans Labyrinth or Planet Terror. I'm working on a zombie flick and need advice. This is my work flow so far. The actor is going to wear green screen socks to be removed. I am going to 3d track the scene (syntheyes), which will then be exported to Lightwave. Then I am going to model/animate/render the legs using Lightwave's compositing tools to line up the legs to the actor (sounds tedious). These legs are going to be transparent in certain areas as they have been severely decayed. I've seen fantastic work done by the artists on CSI but I'm building the effect on my own and I'm worried I may be missing something. Any thoughts? I'll post a some tests soon.
Thanks for any advice,
Gray

camera tracking is absolutely necessary but it would be nice if you can track the leg limbs (toward hips) and hips as well. it will reduce the work you have to do in order to get your cg limbs "attached" to the actor in your plate. you can do this in syntheyes... so you do one tracking pass for your camera then you do separate tracking passes for every object your are trying to track (thighL, thighR, pelvis).

there's a good tut or two at the andersson site on object tracking... basically, you're going to try to add markers to the sock and hips (forget what the minimum amount of markers is... 6?).

then these objects will have motion channels just like the camera and you want to assign them to nulls. then put your cg limbs under the nulls and you should have a preliminary matchmove of the limbs (for the legs, it would look like chopsticks sticking out of the pelvis cuz you're not animating them yet) and since the matchmove motion is on a null, you still have freedom to add either compensatory/fix animation to the legs as well as do final animation on them.

luck!

jin

p.s. errrr... i'm assuming the actor's gonna be moving a bit. if he's just sittin' stock still, no need to track limbs/hips... just eyeball it.

realgray
01-20-2009, 01:34 AM
Thanks for the tips. I'm working through the syntheyes course over at fxphd right now. Not good enough yet to track individual objects but will be soon. It will be interesting to see how it turns out. I'm guessing this is the same workflow used to animate faces on live animals and such. It opens a whole world of possibilities.
Gray

jin choung
01-20-2009, 02:06 AM
It opens a whole world of possibilities.

oh yeah... you can make things talk. you can visit all kinds of unlikely and ungodly violence on things and make it look absolutely real. good stuff! : )

oh, did you see the fishdog spot? http://www.newtek.com/lightwave/newsletter.php

that's another thing you can do... make hybrid animals that are an abomination to nature.

jin