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AI Video Production2026-03-172 min read

Runway Gen-4 Complete Guide

Master Runway Gen-4 camera control, Motion Brush, and Extend features

RunwayGen-4Motion BrushVideo GenerationTake NoteMark Doubt

Runway Gen-4 Overview

Runway Gen-4 is Runway's flagship video model. It supports text-to-video, image-to-video, video extension, and local motion control, and is widely used for commercials, ads, and social content.

Core Modes

  • Text to Video: Generate from text only
  • Image to Video: Upload first frame or reference image; generate motion
  • Video to Video: Style transfer or local edits on existing video
  • Extend: Add frames at the end to lengthen a clip

Camera Control

Gen-4 offers presets and parameters for camera motion:

  • Pan: Pan left/right; control speed and range
  • Zoom: Zoom in/out; simulate push or pull
  • Rotation: Orbit, tilt, etc.
  • Locked: Lock camera; subject moves, background stays still
Specify camera motion in the prompt for more predictable results.

Motion Brush

Motion Brush is a standout Gen-4 feature:

  • Paint regions: Mark areas that should move
  • Set direction and strength: Arrows for direction; sliders for intensity
  • Multiple regions: Several regions can move independently
  • Static areas: Unpainted areas stay relatively still

    • Typical uses:

    • Person walks while background stays fixed
    • Hair, clothes moving in wind
    • Product rotation or highlight
    • Text or graphics entrance animation

    Extend

    • Click Extend at the end of a clip; the model generates more frames
    • Good for extending 4-second clips to 8 or 16 seconds
    • Can Extend repeatedly; watch for continuity over time
    • If there are visible jumps, tweak the prompt or regenerate segments

    Best Practices

    • First frame quality: For image-to-video, use a clear, well-composed first frame; avoid blur or bad cropping
    • Concise prompts: Long prompts can confuse Gen-4; prioritize subject and main action
    • Moderate Motion Brush: Too strong can distort; start small and adjust
    • Resolution and length: Choose 720p/1080p and 4s/10s based on needs and cost

    Summary

    Runway Gen-4 provides fine-grained control via Camera Control, Motion Brush, and Extend. Mastering these features helps you efficiently create ads, short-form content, and product videos.

    Flash Cards

    Question

    What is Runway Gen-4's Motion Brush?

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    Answer

    Motion Brush lets you paint regions on the frame and set motion direction and strength for those regions. You can keep the background still while only the subject moves, or make an object slide in a chosen direction.

    Question

    How does Gen-4's Extend feature work?

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    Answer

    Extend adds frames at the end of an existing clip to lengthen it. It preserves style and motion continuity, useful for turning short clips into longer ones; supports multiple consecutive Extends to grow the clip step by step.

    Question

    How do you achieve precise camera control in Runway?

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    Answer

    Combine prompt descriptions of camera motion (pan, tilt, zoom), Motion Brush for local motion, and Camera Control parameters for overall motion strength. You can also use Image to Video to fix the first frame before generating.