2D vs 3D animation: the differences and how to choose

2D vs 3D: what the dimensions mean

2D (two-dimensional) describes anything whose points are located with two coordinates, usually width and height; 3D (three-dimensional) needs a third value, depth. A drawing, a photo or a cartoon frame is 2D, a flat image. A 3D model describes a shape in space, so a virtual camera can look at it from any side, and the renderer then computes the flat picture you watch.

That changes the way people work. Wikipedia's article on 2D computer graphics notes that two-dimensional models give more direct control of the image, while the 3D approach is "more akin to photography than to typography". In 2D you make the picture; in 3D you build a set, light it and film it with a virtual camera.

2D animation vs 3D animation: definitions

What 2D animation is

2D animation creates movement from a sequence of flat images. In traditional animation, each frame is drawn by hand: a key animator draws the key drawings of a scene, inbetweeners draw the frames still missing between them, then the drawings are cleaned up, inked and painted, over backgrounds painted separately. Much of this now happens on computers, with graphics tablets and digital ink and paint.

Film usually runs at 24 frames per second, and moving characters are often animated on twos: each drawing is held for two frames, so only 12 drawings per second. For a quick movement, animators usually go back to on ones, one drawing per frame; a blend of the two keeps the eye fooled without unnecessary production work. Cut-out animation is the other branch of 2D: flat characters made of jointed parts, once paper or card, now often scanned images or vector graphics on a computer.

What 3D animation is

3D animation moves models built in three-dimensional space. Characters and sets are modeled, each figure is rigged with a virtual skeleton, and the animator sets its values at strategic frames, the keyframes. The software interpolates between them, then every frame is rendered and composited. In Blender the skeleton is an armature, posed in Pose Mode, and the Graph Editor shows the curves Blender computes between keys. The guide to 3D animation details every stage of a production and the jobs behind it.

How each is produced, step by step

A storyboard, the shot by shot breakdown of staging, acting and camera moves, can serve either technique. After it, the work splits.

A 2D shot

1. Keys. The animator draws the main poses first (pose to pose), or works straight ahead from the first frame to the last.
2. In-betweens. The missing frames are drawn, on ones or on twos. The guide to in-betweening covers keys, breakdowns and timing.
3. Clean-up and color. Rough drawings become final lines, then are inked and painted.
4. Background and camera. Characters are laid over painted sets. Depth comes from layers: the multiplane camera moved pieces of artwork at different speeds and distances to create parallax, and computer animation systems offer a digital equivalent.

A 3D shot

1. Assets. Characters, props and sets are modeled and given materials before any animation.
2. Rigging. Each character gets a skeleton, and its mesh is bound to the bones so that it deforms with them.
3. Layout and animation. Models, lights and camera are placed; the animator keys the poses and refines the curves between them.
4. Rendering and compositing. The renderer computes every frame, and the frames are assembled into the final shot.

2D vs 3D animation compared

The two columns spend effort in different places: 2D pays for every frame as it is drawn, 3D pays up front for its assets and again at render time.

The skills each one asks for

The craft of movement is shared. The twelve basic principles of animation, set out by Disney animators Ollie Johnston and Frank Thomas in The Illusion of Life (1981), were written for hand-drawn animation and still apply to computer animation. Pose to pose, key frames first and intervals filled in later, describes a 2D animator's keys and a 3D animator's keyframes alike.

• 2D: drawing first. A character has to stay on model in every frame and from every angle the shot asks for, because nothing generates the new view for you. Then timing, clean lines and color.
• 3D: modeling, rigging and the weights that tie a mesh to its bones, posing and curve editing, materials, lighting and render settings.

Blender does both: Grease Pencil and 3D objects

Grease Pencil is a Blender object type that takes what you draw with a mouse or a stylus, pressure included, and places it in 3D space as strokes made of points. The manual describes it as a 2D animation tool fully immersed in a 3D environment, for traditional 2D animation, cut-out animation, motion graphics and storyboards. It has its own modes: Draw creates strokes, Sculpt reshapes them, Edit works on individual strokes and points, Vertex Paint colors the points, Weight Paint assigns weights for rigging, and Object moves the whole object.

1. Start from File > New > 2D Animation, or use Add > Grease Pencil > Blank in an existing scene. The template sets a white background, a drawing plane facing front (X-Z) and Line and Fill layers, and it creates a keyframe whenever you draw on an empty frame.
2. In Draw Mode, draw the first key, then move along the timeline and draw the next one.
3. Turn on onion skinning to see the neighboring drawings while you work.
4. Fill the gaps by hand, or with Interpolate (Ctrl+E), which adds breakdown keyframes, and Interpolate Sequence (Shift+Ctrl+E), which adds one on every frame between two keyframes. The manual suggests Interpolate for simple shapes.

For cut-out work, a Grease Pencil object can follow a parent, a hook or an armature. The tool was rewritten in Blender 4.3, so tutorials made for earlier versions may not match what you see. The guide to Grease Pencil in Blender covers drawing, layers, animation and rendering in detail.

Hybrid styles: 3D that looks drawn, 2D with depth

Hand-drawn and 3D animation have been combined for decades: the ballroom sequence in Disney's Beauty and the Beast (1991) already used a 3D background. Four families stand out.

Cel-shaded or toon 3D

Cel shading, or toon shading, is a non-photorealistic rendering technique that makes 3D graphics look flat and hand-drawn: lighting is reduced to a few discrete shades, often with outlines, to mimic a comic book or a cartoon. Jet Set Radio drew media attention for it at the 1999 Tokyo Game Show, and The Legend of Zelda: The Wind Waker (2002) is another example. In Blender, a Shader to RGB node (EEVEE only) followed by a Color Ramp gives a toon shader, and outlines come from Freestyle or the Line Art modifier. The guide to cel shading in Blender builds it step by step.

2D drawn over 3D

Disney's short Paperman (2012, John Kahrs) blends traditional and computer animation through Meander, a hybrid vector and raster drawing system; Kahrs explained that his animators could even erase away the CG underlayer. It won the Academy Award for Best Animated Short Film. On Spider-Man: Into the Spider-Verse (2018), artists worked in 2D on top of the rendered frames, with line work, painting and halftone dots, and the frame rate varied between 24 images per second (on ones) and 12 (on twos). In Blender, Grease Pencil objects can be added to any 3D scene, the Line Art modifier generates strokes from the geometry the active camera sees, and the Stepped Interpolation F-Curve modifier holds each value for a number of frames (Step Size), the 3D counterpart of animating on twos.

3D backgrounds behind 2D characters

For Tarzan (1999), Disney developed Deep Canvas, a 3D painting and rendering technique that produces CGI backgrounds that look like a traditional painting; its creators received a Technical Achievement Award from the Academy in 2003. Treasure Planet (2002) set hand-drawn 2D animation atop 3D computer animation.

2D features that borrow from 3D

Klaus (2019, Sergio Pablos) is traditionally animated, with volumetric lighting and texturing so that the characters do not look like stickers on painted backgrounds; it won the BAFTA for Best Animated Film. I Lost My Body (2019, Jérémy Clapin) had most of its animation produced at Xilam using Blender, mixing 2D and CGI.

How to choose between 2D and 3D

When weighing 3D versus 2D for a project, go through these questions in order.

1. What should it look like? Drawn lines and full control of each image point to 2D. Volume, light and a camera that travels through the set point to 3D. A drawn look with 3D camera moves points to a hybrid.
2. How often do characters and sets come back? 3D modeling and rigging happen before the first shot and pay off in every shot that reuses them; cut-out 2D follows the same logic. A piece with few shots spreads that set-up over little screen time.
3. What does the camera do? Pans and layered parallax suit 2D. A camera circling a character means new drawings for every angle in 2D; a 3D model is simply seen from the new position.
4. Who is on the team? Artists who draw well favor 2D; modelers, riggers and lighters favor 3D. Pick the technique your team can finish.
5. Can the project absorb the render? Every 3D frame has to be computed (see below).

By type of project:

• Explainer or motion graphics: both work, and the Grease Pencil manual lists motion graphics among its uses.
• Game: images are produced in real time, and 2D graphics are still used for their style, low bandwidth and faster real-time rendering. Cel-shaded 3D games sit in between.
• Short film: room to experiment. Paperman, Feast and The Dam Keeper are shorts with a distinctive cel-shaded 3D style.
• Feature or series: both are still made, from the hand-drawn Klaus to the reworked 3D of Spider-Verse. Over a long series, reuse counts: television studios relied heavily on limited animation, which reuses frames of character animation, for its financial benefits.

Rendering: why frame count drives 3D render time

In 3D, nothing reaches the screen until the renderer computes it, frame by frame. In Blender, Render > Render Animation (Ctrl+F12) renders the frame range set by Frame Start and Frame End, so the total is roughly the time of one frame multiplied by the frame count. At 24 frames per second, a 3-minute short holds 4,320 frames: one extra second per frame adds 72 minutes to the whole render.

The engine sets the time per frame. EEVEE is Blender's real-time engine, focused on speed and interactivity, and its manual says Cycles will always provide more physically accurate renders. Render one representative frame at final settings, then multiply; the render time calculator does that from the minutes per frame and the frame count.

2D made in Blender is rendered too. Grease Pencil objects go through the same Render Animation, and in the Render > Grease Pencil panel, higher SSAA Samples give smoother lines but increase render time. In traditional 2D, the time sits in the drawing, before anything reaches the screen.

Common mistakes when choosing between 2D and 3D

• Counting only the animation. In 3D, modeling and rigging come before the first key and rendering after the last; a schedule that stops at "animation done" misses both ends.
• Treating 2D as the light option. Every frame is a drawing, and quick movements push you back to ones.
• Choosing 3D for staging that never turns, where the set-up buys little, or 2D for a shot that circles a character, where every frame of the turn has to be drawn.
• Picking a style the team cannot produce. A 3D pipeline needs modeling, rigging and lighting as well as animation.
• Expecting 3D on twos to halve the render. Stepped Interpolation changes the curves, not the frame range: Render Animation still renders the same number of frames.
• Following a Grease Pencil tutorial from before 4.3. The tool was rewritten in 4.3, and files saved in 4.3 or later do not load correctly in 4.2 or earlier.
• Stacking Line Art modifiers. Each one runs the whole occlusion calculation on its own, so several make evaluation much longer.