Rotoscoping a person in After Effects sounds hard, but it’s really just tracing a moving object frame by frame – like a digital coloring book. In this guide, I’ll walk you through every click, every shortcut, and every mistake to avoid. No prior knowledge needed.

What you’ll need: Adobe After Effects (free 7‑day trial from Adobe if you don’t have it) + a short video clip of a person walking (you can download one for free from Pexels or Pixabay).

📁 Step 1: Import Your Footage

Open After Effects. You’ll see a blank project. Go to File → Import → File (or drag your video directly into the Project panel). Select your video clip. Drag it from the Project panel down to the timeline (the bottom area) – this creates a new layer.

🎨 Step 2: Create Your First Mask (The Person’s Outline)

Select the video layer in the timeline. Then grab the Pen tool (shortcut: G). Zoom in on the person by scrolling your mouse wheel or using the Zoom tool (magnifying glass).

Click around the person’s body to create a rough outline. You don’t need to be perfect yet. The points you click are called control points. When you finish the outline, click back on the first point to close the mask. You’ll see everything outside the mask disappear – that means the mask is working.

⏱️ Step 3: Understand Keyframes (The Magic of Animation)

Right now your mask is frozen on the first frame. As the person moves, the mask won’t follow – unless you tell it to. That’s what keyframes do.

Make sure your mask is selected (you’ll see its outline). Go to the timeline, find the little triangle next to your layer name → click Masks → then Mask Path. You’ll see a stopwatch icon. Click it. That’s your first keyframe – it saves the mask’s shape at that moment.

🎬 Step 4: Move Forward and Adjust

Press Page Down to move forward one frame (or drag the blue time indicator). The person will have moved slightly. Now grab the Pen tool again and drag your mask points so they cover the person again. After Effects will automatically add a new keyframe. Keep doing this every 3‑5 frames.

Pro tip: You don’t need to move every point on every frame – only the parts that change. The software will smoothly animate the rest.

✂️ Step 5: Split the Person into Parts (Head, Torso, Arms)

Tracing the whole body with one mask is hard. Instead, create separate masks for each body part. Click the Add Mask button (next to Masks in the timeline) or just draw a new mask with the Pen tool. Name them: “Head”, “Body”, “LeftArm”, “RightArm”, “Legs”. Then animate each mask separately – it’s much easier.

✨ Step 6: Feathering – Soften the Edge

If your roto looks too sharp, increase Mask Feather (in the timeline under Masks). Start with 1‑2 pixels. For motion blur, increase to 3‑5 pixels. Over‑feathering (10+ pixels) makes the person glow – avoid that unless the shot is very blurry.

🔁 Step 7: Use Motion Blur (If Your Footage Has It)

If the person is moving fast, they’ll have motion blur. To match it, select your layer, then click the Motion Blur icon (three circles) next to the layer name. Also enable the master Motion Blur button at the top of the timeline (it looks like a stack of circles). After Effects will automatically blur the mask edge.

🧪 Step 8: Check Your Work (The Solo Switch)

To see only your matte (no background), click the Solo switch (the little circle with a slash) next to your layer. You’ll see your cut‑out person on a black background. If edges are jagged or parts of the background show through, go back and refine the mask points.

📦 Step 9: Export Your Roto (So You Can Use It Elsewhere)

When you’re happy, you need to save the cut‑out person with transparency. Go to Composition → Add to Render Queue. In the Render Queue, click on “Lossless” next to Output Module. Choose Format: QuickTime and Video Codec: ProRes 4444 (this preserves transparency). Under “Channels” choose RGB + Alpha. Then click OK. Choose an output location and press Render.

🙅 Step 10: Common Beginner Mistakes (And How to Avoid Them)

  • Too many points: You don’t need 50 points for a simple curve. Use 4‑6 points for each rounded shape.
  • Not enough keyframes: If the mask drifts, add keyframes every 2‑3 frames during fast motion.
  • Forgetting to feather: A sharp mask on a soft edge looks fake. Always add 1‑2 pixels feather as a baseline.
  • Using only one mask for the whole body: Break the person into parts – it’s faster and looks better.

📺 Video Walkthrough (Free Resources)

Watch these free YouTube tutorials for visual guidance:

  • “After Effects Masking & Rotoscoping for Beginners” by Jake In Motion
  • “How to Rotoscope in After Effects” by Video Copilot (old but gold)

🧪 Practice Project – Your First 30 Minutes

  1. Download a 10‑second clip of a person walking (Pexels green screen or regular).
  2. Import into After Effects.
  3. Create one rough mask around the whole body – just to understand keyframes.
  4. Then redo it with 5 separate masks (head, torso, arms, legs).
  5. Render with alpha and drop it onto a colourful background.

Do this three times with different clips. By the third time, you’ll be 10x faster.

❓ Frequently Asked Questions

Q: Can I use the Rotobrush tool instead of drawing masks?
A: Yes – Rotobrush is faster for simple shots (one person, clean background). But for professional work, manual masking gives you total control. Learn both: Rotobrush for speed, manual masks for precision.

Q: How long will it take me to roto a 1‑minute clip of a person?
A: As a beginner, 2‑4 hours. As a pro, 20‑40 minutes. Speed comes with practice.

Q: What’s the difference between Mask Path and Mask Opacity keyframes?
A: Mask Path changes the shape. Mask Opacity changes how transparent the mask is (e.g., fading in/out).

🚀 Next Steps After This Tutorial

Once you can roto a person, learn to:

  • Roto hair and motion blur (use fewer points, more feathering)
  • Use Mocha AE (built into After Effects) for planar tracking – it can automatically attach masks to moving walls, floors, etc.
  • Combine roto with color correction (Keylight + roto for green screen)

Remember: Every professional roto artist started exactly where you are – drawing wonky shapes around a moving person. Stick with it. In two weeks, you’ll laugh at your first attempt.

— Chami, MPC roto artist

📌 Stuck on a specific frame? Email me a screenshot – I’ll tell you exactly how to fix it.