Set Matte: a 32-bpc node for After Effects

Many people don’t know the Set Matte effect plug-in exists, maybe because it officially exists only to provide compatibility with earlier projects. That seems to have changed though, since Set Matte was upgraded to support 32-bpc color depth in After Effects CS6.

Read the rest at ProVideo Coalition.

CMG Hidden Gems: Masks, Stencils, Track Mattes

Chris & Trish Meyer’s series of tips, tricks, gotchas, factoids, and shortcuts continue with tips on Masking, Track Mattes, and Stencils in CMG Hidden Gems: Chapter 10 – All About Masking, CMG Hidden Gems: Chapter 11 – All About Track Mattes, and CMG Hidden Gems: Chapter 12 – Stencils and the “T” (the Transparency switch).

For additional handy info and tutorials, see Track mattes and traveling mattes, Stencil modes, and Preserve underlying transparency in After Effects Help and The return of the Set Matte filter at AE Portal.

If you don't know already, check out the tip on hitting the Arrow keys while drawing Rounded Rect mask or Polygon/Star shapes. For some handy info, see the sections on creating and working with masks in After Effects Help, and posts tagged mask at AE Portal.

Rotoscoping Depth Mattes With CameraTracker

Jorrit Schulte posted Rotoscoping Depth Mattes With CameraTracker last month on AEtuts:

"In this tutorial, we’re going to look at creating a 3D depth matte from Real footage. We’ll matchmove the footage with The Foundry’s plug-in CameraTracker, and create 3D layers that match the Footage to get a '3D model' of the scene. Then you will learn what you can do with this depth matte after you create it; create realistic fog, fake DOF and a rotoscoped matte."

Related techniques can be found in After Effects Rack Focus: tutorial and preset and with the Digieffects Depth Cue plug-ins and tutorials noted in Sharpen Depth of Field with One Click (there's many more at Digieffects). Here's a preview Jorrit's work:

Photoshop CS5 Refine Edge enhancements + overview

In a new podcast, Adobe's Terry White demos Edge Detection and Decontaminate Colors in Refine Edge in Photoshop CS5. These features, also in Refine Mask, are akin to ones in the new Refine Matte in After Effects CS5 (see the Mark Christiansen explanation free at Lynda.com).

See also White's 45-minute Overview in the Adobe TV Photoshop CS5 Feature Tour.

Alpha channels: premultiplied vs straight (retired)

Alpha channels are grayscale channels in addition to the color channels of a file. They define transparency and often delineate objects or selections as a matte or stencil. Alpha channels can come pre-matted ("shaped") or as straight, that is, anti-aliased when composited.

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This post was updated on Pro Video Coalition as Alpha channels: premultiplied vs straight.

Rotoscoping tips

Via Joost van der Hoeven is 6 great rotoscoping tips from Imagineer Systems by TheBlackbox.org:

1. There is no such thing as a perfect matte. Rotoscoping is an art form that takes into account the background image, the movement of the object, and the new elements to be composited in the background.
2. Try to start your shape at its most complex point in time, where it will need the most control points.
3. Break a complex shape into multiple simple shapes. If you are rotoscoping a humanoid form and an arm becomes visible, consider rotoscoping the arm as its own element, rather than adding extra points on the body that will serve no purpose when the arm is obscured.
4. Imagine you are the animator who created the shot. What would your dope sheet look like? No matter the medium, whether CG, live action or otherwise, most movements are rarely linear. They normally move in arcs; they normally accelerate in and out of stopped positions. Try and understand the mechanics behind how things are moving in your shot. This will help you to minimize keyframes.
5. Watch and study the shot before you start working. Where are the changes in directions? These will normally have keyframes. Where are the starts and stops? Are there camera moves that can be stabilized to make your work easier?
6. Don’t be afraid to trash your work and start over. Beginning roto artists often make the mistake of trying to fix a flawed approach by adding more and more keyframes. Experienced roto artists learn to quickly identify an inferior approach and are unashamed to trash their work and start over, often many, many times. It is very difficult to get a good matte without a conscious effort to keep the keyframes to a minimum.
   

Rotoscoping, roto for short, has been more fully explained by Matt Silverman of Commotion Complete fame in The Art of Roto at Fxguide [updated 2011] and by Commotion's creator and ILM alumni Scott Squires in blog posts and movies at his Effects Corner blog. More recently, Fxguide's The Art of Wire Removal covered some of the same ground.

And from the same talent pool is a handy summary of tips in Confessions of a Roto Artist: Three Rules For Better Mattes (PDF) by Scott Stewart (now a movie director), who did the roto tape for the out-of-print Masters of Visual Effects:




While still missing key features, there's plenty of rotoscoping done in AE, and many good After Effects tutorials. Sean Kennedy takes you through Rotoscoping Tools in After Effects, and Pete O'Connell (now found under Nuke) has a tutorial movie Rotoscoping in AE and a DVD, Advanced Rotoscoping Techniques for Adobe After Effects, at Creative Cow. Also, there are several tutorials involving rotoscoping with Imagineer Mocha & Mocha Shape, some noted in AEP's More mocha tracking & roto, as well as several by Mathias Möhl using his AE script MochaImport. Digital Tutors has a course for CS4 too, Rotoscoping Techniques in After Effects.

Todd Kopriva has a few more tips (from Pete O'Connell) in his Rotoscoping in After Effects and in After Effects Help. And of course there were previous posts here at AEP, tagged roto.

Update: The Art of Roto: 2011 by Mike Seymour at Fxguide is a super update to previous surveys of rotoscoping. It includes an interview with Scott Squires, who created Commotion (a desktop roto/paint/com tool) while at ILM.

'Super tight' garbage mattes in After Effects

Topher Welsh has a quick tip on creating "super tight" garbage mattes to aid keying. He uses a basic After Effects color key like Color Range then applies the Simple Choker filter with a negative setting, expanding the matte to let an advanced keyer like Keylight to work more subtle magic. This technique that can also be found in Making It Look Great 5 with Maltaannon.

The technique is inspired in part by an older video by Aharon Rabinowitz, Super Tight Junk Mattes which used Auto-Trace and the Simple Choker to refine garbage mattes (project files are still available at Cow). Aharon similarly leverages convenient Red Giant filters in a more recent tutorial, RGTV Episode 4: Better Compositing Techniques.

Also there's no reason you can't use a copy of the matte with Simple Choker to do a choke for a hold out matte to preserve the keyed subject (as seen in Commotion Complete by Matt Silverman and recent keying training from Toolfarm). Here's Aharon's older tutorial and the new one by Topher:

The return of the Set Matte filter

There's an update to this article on Pro Video Coalition, Set Matte: a 32-bpc node for After Effects, which unlike Track Matte lets you use one matte on multiple layers.

Many people don't seem to know the Set Matte effect plug-in exists, maybe because it officially exists only to provide compatibility with earlier projects. That seems to have changed since Set Matte was upgraded to support 32-bpc color depth in After Effects CS6...