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Are there any compositing experts out there?

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Travis Mays
Are there any compositing experts out there?
on Oct 22, 2012 at 9:12:33 pm

I'm looking to shoot a fake room with a green screen ceiling so that it can be extended higher later in post. How feasible would this be to do on an iMac with the latest version of AE? Thanks.


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Angelo Lorenzo
Re: Are there any compositing experts out there?
on Oct 22, 2012 at 9:39:21 pm

Fairly easy. You'll need Photoshop to craft your extension.

The difficulty also depends on your camera move. A locked shot is far easier than tracking a handheld or stedi-cam shot. The latter may need something more specialized like Nuke by The Foundry.

Also be prepared that even with green screen you should have to do some manual rotoscoping and frame painting especially if the ceiling is poorly lit. You'll want to prepare your green screen for motion tracking by peppering it with darker green X and triangles - shapes that a tracker can hold onto.

As far as computing power, it's doable on an iMac, but there are too many variables to guess how long it will take you to work or render.

Angelo Lorenzo
Fallen Empire Digital Production Services - Los Angeles
RED transcoding, on-set DIT, and RED Epic rental services
Fallen Empire - The Blog
A blog dedicated to filmmaking, the RED workflow, and DIT tips and tricks


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Travis Mays
Re: Are there any compositing experts out there?
on Oct 22, 2012 at 10:02:46 pm

Thanks. That's a pretty good answer. It will probably be between 15-30 shots. And total length wouldn't be more than a minute or two. Do you think that's worth it? Or should I just find a stage where I can build that high?


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Angelo Lorenzo
Re: Are there any compositing experts out there?
on Oct 22, 2012 at 10:14:51 pm

As a producer in my own right, here are my concerns:

You say 15-30 shots in 1-2 minutes. This either means you haven't broken down the scene for shooting properly or, more likely, you're shooting some kind of fighting/action sequence.

Action means shooting with a bit narrower of a shutter angle to kill the motion blur slightly but it also means a ton of manual rotoscoping so I hope you have that skill under control.

How high do you need the ceilings? Cathedral?

The problem with building a practical set is, of course, the cost of construction. Beyond that though is the possibility of having to build on-set which means extra days to the stage rental, or a design that allows you to build off-set and transport. You also have the extra expense of hiring a real carpenter and crew because they'll come with the proper insurances.

The set extension process is probably cheaper in most situations, but slightly more time consuming. If you've never ever done this, then I suggest you hire a small VFX house so you get a VFX supervisor to guide you through the process of preparing your set for extension.

Alternately, it sounds like you're going to one-man this. I suggest doing a little test footage and working on it so you know what to expect. I also STRONGLY suggest you purchase and watch http://www.hollywoodcamerawork.us/vfx_index.html as a primer to vfx during principal photography.

Angelo Lorenzo
Fallen Empire Digital Production Services - Los Angeles
RED transcoding, on-set DIT, and RED Epic rental services
Fallen Empire - The Blog
A blog dedicated to filmmaking, the RED workflow, and DIT tips and tricks


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Travis Mays
Re: Are there any compositing experts out there?
on Oct 23, 2012 at 12:08:44 am

It means I shoot a lot and use lots of edits. 5 seconds a shot ~ about 20 shots over 2 minutes.

The ceilings are not cathedral high, more about 12-15 feet high. And I currently have a room that's about 8 feet high. I'm pretty good at lighting and rotoscoping - I'm more concerned about realism. The shots will all be facing one direction, so I only need to build one end of the room. And there will be several tracking shots, but nothing too fast or complicated. I'm mostly concerned about it not looking like it's green screened.

Thanks for the links, I'll watch them.


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Angelo Lorenzo
Re: Are there any compositing experts out there?
on Oct 23, 2012 at 12:49:56 am

Well shooting a lot of angles complicates the process because you have to design an extension for each angle/move. My advice on that point would be to come in with a more concise shot list; shooting extra is great but make sure you have a base set of shots that you know you can work on in post fairly easily so you don't paint yourself so far into a corner that you have to reshoot.

Of course, I could be just misinterpreting what you mean by shot. I usually think a shot is a setup while you might just be talking about it as a cut.

Angelo Lorenzo
Fallen Empire Digital Production Services - Los Angeles
RED transcoding, on-set DIT, and RED Epic rental services
Fallen Empire - The Blog
A blog dedicated to filmmaking, the RED workflow, and DIT tips and tricks


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Travis Mays
Re: Are there any compositing experts out there?
on Oct 24, 2012 at 6:59:36 pm

Thanks for all the advice. I am speaking of a shot as a setup AND an edit. While the occasional shot may repeat, for most part every new edit would be a change of camera position.

As far as compositing in a 3D program, I wasn't intending to do anything as intricate as that. The idea is to shoot everything practical, no CGI. Meaning I would be shooting the room with a green screen ceiling, and then building the extension in another room and matching camera angles. So if I was shooting waist high towards the ceiling in the green screen room, I would be shooting ankle high in the false ceiling room, and compositing that into the green screen where the ceiling should be. I wanted to get an idea mostly of the practicality of doing this, obviously I will have to keep meticulous notes on the type of lenses used, angle of tilt on the tripod, and position of the camera in the room from shot to shot.

Workflow-wise, this would all be shot on a Red Scarlet, using DPX files, then edited in Final cut on an iMac before compiling the final shots in after effects, or some other program.

The main reason for doing it this way is budget and time. I would rather find a soundstage and construct a set, but I don't have a lot of luxury money-wise to rent a real one, and pending finding some large enclosed space I can occupy for an extended stretch of time for a limited amount of money, this seems to be the most practical way of doing this.


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Conrad Olson
Re: Are there any compositing experts out there?
on Oct 24, 2012 at 8:40:31 pm

You will have to do some serious scale and lens maths to make this work. You will also need to be very accurate with the measurements that you take from your tripod. And any kind of camera movement will pretty much fail unless you have a motion control rig.

You might be able to get something close and use corner pinning or warping to fix any issues.

I would be interested to hear if this setup works but I would probably go the VFX route if it was my project.

---

conradolson.com


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Angelo Lorenzo
Re: Are there any compositing experts out there?
on Oct 24, 2012 at 11:44:30 pm

It's bad, just not insanely bad. The focal length of the lens doesn't matter, it just crops so you can scale any differences (yes, I'm ignoring the aspect of barrel distortion) so your main measurements are angle and camera/focus distance. You can scale from there.... but at that point I would really wonder how much this ceiling adds; huge factory vent fans, fine, but if it's an extension of the normal ceiling then I'd wonder the point.

Doing measurements manually is agonizingly slow and it also locks you in each camera position.

Angelo Lorenzo
Fallen Empire Digital Production Services - Los Angeles
RED transcoding, on-set DIT, and RED Epic rental services
Fallen Empire - The Blog
A blog dedicated to filmmaking, the RED workflow, and DIT tips and tricks


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Travis Mays
Re: Are there any compositing experts out there?
on Oct 25, 2012 at 2:35:20 am

I'm not talking scale though, it's 1:1. And yes, I realize now tracking would be difficult to impossible.


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Travis Mays
Re: Are there any compositing experts out there?
on Oct 29, 2012 at 11:14:22 pm

This is what I'm workin with:
http://i.imgur.com/pWoWQ.jpg


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Conrad Olson
Re: Are there any compositing experts out there?
on Oct 23, 2012 at 6:38:42 pm

This is how we would do something like this on a feature film:

Camera track each shot, regardless of the type of camera move, making sure that the cameras all end up in the same relative postion to each other.

Build some 3D geometry for the room and the extra ceiling extension. This could be a massively complex and detailed 3D model, that gets textured and rendered from Maya, or if we are doing the simpler 2.5D approach we will have a matte painter paint up stills and apply them to cards in Nuke (but you can do the same in AE). You would have a card for each wall and then the ceiling. If you can use some frames from your original shot to create this painting it will help you get the colours to match.

Creating a solid 3D setup and getting camera tracks takes time at the beginning of the process but once it is done you can quickly get all of the shots into the same place, and if there are changes to the matte painting later you can just update the setup and drop it into all of the shots.

We will then drop the camera for each shot into the 3D environment and you will get the correct view. Remember that if you are using the card/matte painting solution there will be no parallax within the painting. If it is far enough away this wont matter.

Then take the output of this 3D setup and composite it with the rest of your shot as if it was any other kind of footage.

If there is a defined edge to the top of your set and the start of the green screen, like a line of bricks or a ledge, use that as the joining point between the set and the extension. If it is a smooth texture that you want to continue you might need to create a feathered edge to hid the seam. This will probably require roto but if you have a 3D setup you can render a feathered matte from there that will work for every shot, without the need need to roto each one.

Other things you will need to do to sell your composite are:
*match the black levels to your plate
*match any grain or noise to your plate
*match the motion blur
*add any interactive lighting to your extension
*match the depth of field

---

conradolson.com


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Conrad Olson
Re: Are there any compositing experts out there?
on Oct 23, 2012 at 6:40:26 pm

I forgot to add "match lens distortion". This should be done after the output of the 3D setup or after the 2D track.

---

conradolson.com


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Tom Daigon
Re: Are there any compositing experts out there?
on Oct 22, 2012 at 10:43:08 pm

Travis , there has been no mention of the file type you will be using which could have a big impact on how your imac functions with AE.

If you are working on DPX, Red or any large format files then I would have concerns.

Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com





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Travis Mays
Re: Are there any compositing experts out there?
on Oct 23, 2012 at 12:17:02 am

I plan on using 2K, though I would have a cut before I compiled everything to cut down on length and file size.


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