VFX Post-production tips.

These are our top tips for managing the post-production process. Essentially we’re trying to control these truisms.

• How do we check everyone imagines the same thing?

• Stuff never turns out quite the way we imagined it.

 

 

Visualize it. Be specific.

There’s no point in spending a days and days finishing a shot if not what the client wants.

Low res visualizations will help the editor and director make decisions ( often called postvis ). Postvis may be created by the vfx team or the vfx editor, and may happen at any point after a shoot.

On a budget there can be a temptation to skip the visualisation stage. But the ‘we can’t afford this attitude’ will backfire unless directors are happy to simply accept vfx shots without wanting changes.

 

Start with a Locked Cut.

Ideally the Cut should be locked before the VFX work starts. If a sequence isn’t working and can’t be locked down then we should be visualizing as cheaply and disposably possible to help the editor and director.

 

Handles…

We almost never use handles on shots now unless we anticipate there will be a timing issue. However the VFX team must be able to watch each shot in context to see how it cuts.

 

Don’t use handles

We have found that handles can be more trouble than they are worth. They create more work for the editor, and they create some confusion about where the shot actually starts.

 

Do use handles

It can be hard for the editor and director to visualise timings when there’s nothing there to see. Once the vfx is complete, it may be necessary to slip the shot by a few frames for the final cut, or a have slightly different shot for trailers.

The convention is to add 5 frame ( or sometimes 10 frame ) handles to the shot before it is delivered to the VFX team.

So, if a VFX shot in the locked cut is 15 frames long then it would be extended 5 frames at the beginning and end, and 25 frames would be passed to the VFX team

 

Burn Timecode on Each Version of the Cut

Where changes need to be made, it helps to be specific. Ideally all preview versions should have the destination timecode burnt onto the movie file.

 

Destination timecode

The destination timecode is simply when, in time, the shot appears in the show. The convention is that the timecode for the show starts at 10 hours or 10:00:00:00

 

Source Timecode

The source timecode is simply where the shot appears in the original footage.

 

FX artists need see each shot in context.

• The vfx artist needs to see all the shots in the sequence to see how it cuts

• Rig removal shots don’t need to be seen in context. But anything that’s time critical does.

• Anything that involves some CG performance probably needs previs.

 

File Formats.

Generally I use 10bit DPX files for delivering VFX elements. I’m open to using other files, but DPXs are light weight to pass around and do the job rather well.

Though it’s invariably lost it’s enormously helpful if ISO settings, lens sizes, black and white points are stored in the files metadata.

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Keep the camera’s Log colour profile.

It’s easier for everyone if the camera’s colour profile is preserved as files are passed around. This minimizes the mathematical confusion that can happen, and preserves image quality without using heavyweight floating point file formats.

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LUTs

LUTs from the shows grading artist can be invaluable to help the VFX team design shots to fit the Look of the show.

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Shot review Previews.

Half sized quicktime movies are great for online reviews. These can be supplied to the client graded or ungraded.

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VFX Shot Numbers.

Different editors use different numbering systems to log all the shots and scenes in the show. Some of these systems may work for VFX production some of them don’t. All the VFX team really needs is a sequential list of VFX shots. It can be easier if the VFX team dictates the numbering system.

1. Label each VFX shot in increments of 10 starting at the beginning of the show and working through to the end.

2. Pad the the number to 3 figures. So shot 10 becomes 010. (VFX heavy shows may need 4 figures. )

Let’s say you have 5 VFX shots. In sequence your shots would be:

010, 020, 030, 040, 050.

If later you spot new VFX shot, and it’is in between two existing VFX shots, you can split the difference for the new shot number.

For example if you spot a new shot in between 020 and 030…the new shot would be 025. Let’s say there is one more between 025 and 030, you could do 028…so on and so forth.

By naming your VFX shots in this way, you ensure that your VFX numbers are labelled in sequential order, making life easier for post-production teams.

I have a more detailed breakdown of file name conventions in my blog Simple file naming for VFX

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Post-Production vfx Shot List.

As all the VFX shot are logged, a vfx shot list is prepared. This has all the timecode information needed to pass files around along with notes on what the VFX should look like. This may be part of an online database (like shotgun) or a simple spread sheet.

Information in the VFX shot list may include:-

• Shot name

• thumbnail image

• scene number

• description

• shot length ( frames )

• lens

• source timecode in

• source timecode out

• destination time code in

• destination timecode out

• work in progress notes.

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For example:-