matrix bullet time type shot… kinda, need help

[Ido]

hi everyone, need some advice about a VFX shot i was asked to do.
the shot calls for time to freeze having only two charchters talking while all movment around them stops.
the location in which this will be shot in is public domain and i will not have control of backround elements in the shot.
this is pretty easy to do with a locked shot. just rotro the action onto a single frame backround. i think… right?
but whats the best way to go about it if i need to integrate camrea movment?

thanks in advance
GHSU

[Amit]

hi

first sorry for my poor english

I think you can shot with the movement you like, then, at the t time, modelize all your background elements in a 3D program (huugghh…), apply the texture from the t image, and then 3D track the movement and animate your camera in 3D with that, then recompose. But it’s a big work of roto for your main characters , and a big work of modelize.

I hope i was clear.

Bye

[Michael Dalton]

vincelapince wrote:

hi

first sorry for my poor english

I think you can shot with the movement you like, then, at the t time, modelize all your background elements in a 3D program (huugghh…), apply the texture from the t image, and then 3D track the movement and animate your camera in 3D with that, then recompose. But it’s a big work of roto for your main characters , and a big work of modelize.

I hope i was clear.

Bye

Seems to me that the “smartest” way to handle things would be a little of a variant from what was suggested. Of course what path to take fully depends on just how much the camera needs to spin around the frozen people. If you’ve got big sweeping moves to make seems like Motion Control isn’t such a bad idea…

First I would storyboard/shoot board out the sequence with the DoP/Director and decide which angles, composition and movement would be used for each shot in the scene. It wouldn’t hurt to go ahead and establish things like the final desired lighting as well (High noon, sunset, overcast…). Make animatics, time things, plan plan plan.

Once all of that stuff was decided I would go to the location when the environment could be controlled as best as possible and shoot all the plates required of the the environment with a digital stills camera, scene by scene according to the planning you completed in the first step. Once all of the environmental elements have been shot, it’s into 3d to stitch them back together over relatively simple geometry and cards to build a handy dandy digital studio for use later on. At this stage it could also be smart to start thinking of simple digital props (other than your extras) that you can throw on to your digital set to add a certain degree of life to it… if it’s an outdoor shoot, car projections on simple geometry, matte paintings of clouds and such. One seller could be frozen atmospherics like a frozen in time steam element from the subway or a puddle being splashed, again using simple geometry.

It would also be smart to establish the lighting (to later be replicated on the croma shoot) with the production team. Try to get as good a hold as possible on what conditions you’re going to try to be matching later on – it’s the only chance you have of pulling off a believable green/blue screen comp. Like where is the sun?

After that I would go into the studio and shoot Croma of the principles doing their action, using MoCo and matching the lighting you’ve sketched out on your digital set. Place markers out on the floor for where the extras will be standing and tracking markers (small) out for 3d tracking the shot later, if you can’t translate over the moves from the rig to your 3d/2d software. Shoot a few passes of you principle actions then add in the extras at the marker points and do the same action with them in place. The joy of this approach is that by shooting in several plates you can already on the set begin to layer up your final composites in a pretty intelligent manner and save yourself work later on. For example if your hero is going to be placed just behind five or six extras but in front of say 20 other extras, you can shoot the 20 extras just standing still as one pass and the other five foreground people, again still, as a separate plate.

Remember on the rig you can scale the moves, not only in physical scale but also in time (provided you adhere to the physical limits of the rig) so depending on what the desired effect is you can play with the shutter and fps of the move to either get a streaking effect on the extras, or a tighten the shutter a bit to reduce the motion blur.

Another thing to remember is that the rig’s control software can program the firing-off of gpi triggers into the move. This can be pretty helpful for say a popping on and off lights (for say a close range gun shot) for your different plates. It can also slave to external TC of say a digibeta or SP, for things like sound sync. Good things to think of.

Then back to the 3d set, plug in the camera moves for your respective shots, (either by translating them or tracking them) and start comping. Chances are you could “unwrap” a few frames of the extras plates, to use as projections on simple “marshmellow-man” geometry if you needed to. Otherwise the rest of the job will come down to making things look as believable as possible. Good croma key work, camera tracking, lighting (both in 3d as well as relighting your 2d croma plates with color correction) and rendering.

The thing with these shots is that no matter how good you do them they’ll always look like an effect – it’ll never look “reel” which can really be a problem when trying to get approval. That doesn’t mean it can’t look good – it just means that you really have to be at the top of your game and the idea of what’s actually transpiring really needs to be smart.

Of course I’m sure there’s 1000 other ways to solve variations on the problem as well. On a simple locked off shot or nodal pan, you obviously wouldn’t need motion control. Or if in a particular section, the motion needed to have that weaving kind of handheld feeling, you could slightly over frame the croma plates by a few percent and add a little shake to the final comp after the fact. In short there a ton of tricks to use, but you’ll want a few scenes that are real money shots to sell.

Regardless best of luck,
Chris

[bnw]

Post of the week! Good stuff 🙂

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