Roto Brush
Automatically isolate subjects from backgrounds using AI-powered rotoscoping. Save hours of manual masking.
Masking
Shortcut: Alt+W (Opt+W)Advanced14 min readQuick Reference
Roto Brush
Adobe After EffectsKeyboard Shortcut
Alt+Wkey
Where to Find
Select the Roto Brush tool from the toolbar or press Alt+W (Mac: Opt+W). It's located near the mask tools, shaped like a
Best Used For
- ▸Isolating subjects from backgrounds automatically
- ▸Rotoscoping complex shapes like people and hair
- ▸Removing backgrounds without green screens
- ▸Creating quick masks for compositing
Advanced⏱ 2-4 hours to master
Key Settings
Select Stroke: Green (keep)Remove Stroke: Red (remove)Freeze: Lock analysis
Roto Brush uses AI-powered technology to automatically separate subjects from their backgrounds. Simply paint a green stroke on your subject and a red stroke on the background, and After Effects does the rest. This tool saves hours of manual rotoscoping and makes complex masking accessible to everyone.
Where to Find
Select the Roto Brush tool from the toolbar or press Alt+W (Mac: Opt+W). It's located near the mask tools, shaped like a paintbrush with dotted lines.
How to Use
- Select Subject: Paint a green stroke on the subject you want to isolate
- Remove Background: Hold Alt and paint a red stroke on areas to exclude
- Analyze: Click the "Frame Forward" button to have After Effects track the mask over time
- Refine: Fix errors by adding more green/red strokes on problematic frames
- Freeze: Click "Freeze" to lock in the roto analysis and improve performance
Pro Tips
- Work on a high-contrast frame first for best results
- Use short, precise strokes rather than long scribbles
- Check every 10-15 frames for accuracy and correct as needed
- Convert Roto Brush to a standard mask for further refinement