For animators
AI tools for animators who want their characters playable
Go from a character design to a rigged, animated character running inside a game project. The AI handles the mesh, the rig and the plumbing so your time goes to motion, timing and feel.
The short answer
Summer is a free desktop game engine plus Studio, a set of AI generators for the rest of the pipeline. For an animator that means a character design becomes a textured 3D model, gets auto-rigged, picks up mocap clips or text-generated motion, and imports into a game scene where an agent builds the AnimationTree and plays it. Studio's video tools add motion reference and previs clips from your own footage and designs.
Animators who want to work on games usually hit the same wall. The motion is the part you are good at, but getting it into a game means a model, a rig, skinning, a retarget, an export, an engine import, a state machine and code that decides when each clip plays. Each step is a different tool and most of them are not animation.
Summer compresses the non-animation steps. The 3D tab turns a drawing into a model already posed for rigging. The rigger and the motion library put a working locomotion set on it in one run. The engine imports the character as a package with its clips named and its loops marked, and the agent wires those clips into an AnimationTree you can open, inspect and change.
What you keep is control. Every clip is a standard GLB or FBX that opens in Blender, every AnimationTree is a normal Godot 4 node, and nothing stops you from replacing a generated clip with a hand-keyed one when the generated version is not good enough.
What it does
Design to 3D model
Upload a character sheet or a single drawing, choose Character intent, and Studio prepares a clean bind pose before converting it with Hunyuan 3D, Rodin, Meshy or Tripo.
Rig and motion
Auto-rig a humanoid in Studio, or have your agent pass its real height through the MCP. Add clips from the Meshy mocap library or describe a move and generate it with Hunyuan Motion.
Video reference and previs
Transfer motion from your own reference video onto a character image with Kling 3.0 Motion Control, restyle a short clip with Gemini Omni Flash, or make character-consistent shots from reference images.
Into a playable scene
Import the character package into a Summer project, and have the agent build the AnimationTree, drive it from movement, and run the game so you judge the motion in context.
How it works
- 1
Step 1: Model the design
In Studio's 3D tab, upload your design with Character intent and Improve reference on. Add back and side views if you have a turnaround. Check the result from every angle before rigging.
- 2
Step 2: Rig and add a starter set
Keep Rig plus starter animations on to get Idle, Walk, Run and Jump. Add combat or gesture clips from the library, and generate one-off moves from text in the Animation tab.
- 3
Step 3: Import into a project
Open the Summer desktop app with a project, then import the character from Studio. It lands under
res://characters/with the rig, a character scene and a manifest of clips. - 4
Step 4: Wire states and play
Ask the agent to build the AnimationTree and controller, then play the scene. Tune blend points, transition times and one-shot fades until the character feels right.
Two ways to run it
In Studio, or from the agent you already use
In Summer Studio
Studio runs in the browser and shares one asset library with the desktop engine. Use the 3D tab for the model and rig, the Animation tab for motion and retargeted GLB export, and the Video tab's Reference mode for motion transfer and previs clips.
Open the Video tab in StudioFrom Claude, Cursor or Codex via MCP
If you work with Claude Code, Cursor or Codex, the Summer MCP gives that agent the same pipeline. summer_generate_3d builds a rigged character with named clips, summer_generate_motion adds library clips, summer_import_asset_by_id places the result in a scene, and summer_search_library with summer_read_library gives the agent Summer's written recipes for animated characters and AnimationTree state machines so it follows them instead of improvising.
Example prompt for your agent
Import my rigged fox character into the main scene as the player, prove the idle clip plays, then build an AnimationTree with a speed-driven idle, walk and run blend, jump and fall states and an attack one-shot, and run the game.Set up the Summer MCP
| Model | Input | Output length | Animator use |
|---|---|---|---|
| Kling 3.0 Motion Control | One character image plus one motion video | Follows the reference video | Put your acted motion on your character as reference |
| Gemini Omni Flash edit | One short motion clip | Follows the source clip | Restyle a clip or replace its subject |
| Seedance 2.0 and 2.0 Fast | Up to 9 images and 3 videos | 4 to 15 seconds | Previs shots that keep a character on model |
| Gemini Omni Flash reference | Up to 10 images | 5, 8 or 10 seconds | Fast character-consistent shots |
| Veo 3.1 Reference | Up to 3 images | 8 seconds | Premium subject consistency for a hero shot |
Pricing
What it costs
- 3D model, Hunyuan 3D v3.1 Pro
- $0.75
- 3D model, Hunyuan 3D v3.1 Rapid
- $0.32
- Auto-rig a character
- $1.14
Motion clips and video reference generations are priced per clip or per second in Studio before you run them.
Prices are charged from your Summer usage balance. Generating assets needs a paid plan or a top-up: Pro is $20 a month and includes $20 of usage, and top-ups start at $10. The desktop engine itself is free to download.
See all plansExamples
Prompts that work, and what comes back
Jobs an animator brings to a game project, and which Summer tool does each one.
Character sheet to playable hero
Prompt
Front, side and back views of my character, Rodin 2.5 High, Character intent, Rig plus starter animations on
What you get
A rigged character package in the project, ready for the agent to wire into a third-person controller.
Combat set for an enemy
Prompt
Add attack_sword, block, hit_react and death to the rigged orc, then make attack and hit_react one-shots
What you get
Library clips on the orc's own rig, layered over locomotion in the AnimationTree.
Motion reference from your own footage
Prompt
Kling 3.0 Motion Control, my character image plus a video of me doing the victory pose
What you get
A video of your character performing your motion, useful as timing and posing reference for a hand-keyed clip.
Pitch or previs clip
Prompt
Seedance 2.0 reference to video with three renders of the character, 8 seconds, 16:9, hero walks into a ruined hall
What you get
A character-consistent shot for a pitch deck or animatic, generated as MP4 video.
Emote from a description
Prompt
A person bows deeply, then straightens and salutes (3 seconds)
What you get
A Hunyuan Motion clip to retarget onto the character in the Animation tab export.
The path from design to a rigged, animated character
Start with the drawing you would give a modeler, one character, full body, front-facing, arms away from the body. The 3D tab grades the image and re-poses it into a rig-safe A or T pose when needed, or takes a turnaround sheet as multi-view input. Auto rig then skins a humanoid skeleton, and clips from the Meshy library are generated against that same rig, so the starter set plays without a retarget. For a move no library has, Hunyuan Motion generates one from a short description and the Animation tab export fits it to your character.
Rig requirements, text-to-motion prompting, retargeting in Godot 4 and loop handling are covered step by step on the AI character animation generator page.
How the agent wires AnimationTree states
Summer's agent follows a written recipe for animated characters, and its first rule is to prove one clip plays through the AnimationPlayer before building anything on top. A tree layered over a clip that does not play hides the real problem, which is usually a T-pose from a missing track or a wrong clip name.
Once a clip plays, the agent builds the locomotion stack the recipe describes. An AnimationTree linked to the character's AnimationPlayer, a state machine for discrete states such as jump and fall, a BlendSpace1D that blends idle, walk and run by speed, and OneShot nodes for attacks and landings that play over any state. It sets the tree active in `_ready()`, drives state changes with `travel()`, and derives animation from the body's velocity rather than raw input so knockback and AI movement animate correctly too.
Loop modes are set explicitly. Idle, walk and run loop, jump plays once. Everything the agent builds is standard Godot 4, so you can open the tree, move a blend point, lengthen a crossfade or swap in your own clip and play again.
What video reference is and is not
The video tools produce MP4 video, not skeletal animation. Kling 3.0 Motion Control is the most useful for an animator. Record yourself acting the beat, add an image of your character, and get the character performing your motion as reference for timing and key poses. fal's documentation for the model asks for a character with clear body proportions, no occlusion and more than 5 percent of the image area, and a reference video showing the full or upper body with the head visible. Summer uses the video-orientation mode, which fal documents for complex motion with references up to 30 seconds.
There is no video-to-mocap step in Summer today. A reference clip informs a hand-keyed or text-generated animation; it does not become one.
AI tools animators already use, and where Summer fits
Summer is not the only AI tool an animator will touch, and it does not try to replace the animation software you already know. These are common tools in a game animator's kit, listed in no particular order, with what each one does according to its maker.
Summer sits after these tools. It builds the character, the game project and the state machine, and imports the FBX or GLB clips they export, since Godot 4.3 and later read FBX directly and retarget humanoid clips at import.
- Cascadeur is keyframe animation software with AI assistance, including AutoPosing for natural poses from fewer control points, AutoPhysics for secondary motion and inertia, AI inbetweening and mocap cleanup. Its free license has no time limit but does not allow commercial use.
- Rokoko Vision turns ordinary video from any camera into 3D motion capture and exports FBX or BVH. Rokoko's free Starter plan includes 30 seconds of video processing a month.
- DeepMotion Animate 3D creates 3D animation from video with no suit or hardware, with free accounts and export to FBX, BVH, GLB and MP4.
- Move.ai makes markerless motion capture, with multi-camera systems and the single-camera Move One platform.
Where your skills still matter most
Generated locomotion is a good base and a poor finish. Contact frames, weight shifts, anticipation on attacks and the exact frame an attack becomes active are still animation decisions, and they are what separates a character that feels good from one that only moves. Summer is built so you spend your time there, and everything it generates can be opened and replaced.
Frequently asked questions
Do I need to know 3D modeling or rigging?
No. Studio turns a design into a model and rigs humanoid characters automatically. Knowing how a clean rig should look still helps you judge the result and decide when to regenerate a mesh before rigging it.
Can I bring in my own hand-keyed animations?
Yes. Summer projects are compatible with Godot 4, which imports GLB and, from version 4.3, FBX directly. Godot's BoneMap retargeting at import lets clips from another humanoid rig play on your character.
Does the agent build AnimationTrees?
Yes. It follows Summer's recipe of a state machine for discrete states, a BlendSpace1D for speed-based locomotion and OneShot nodes for actions, after first proving a clip plays. The result is a normal AnimationTree you can edit.
Will AI replace game animators?
Not the part that makes a character feel good. AI now covers rigging, stock locomotion and rough takes, but contact frames, weight shifts, anticipation and the exact frame an attack becomes active are still animation decisions. The tools move time away from plumbing and toward that polish.
Can I use Studio if my game is in another engine?
Yes. Studio exports GLB characters with their clips, and video as MP4. Blender opens the GLB files directly, and Unity and Unreal read them through their glTF importers.
Can I use the characters and clips in a commercial game?
Summer's terms state that you retain ownership of the content you create with Summer Engine, and you can launch your game wherever you want. If you publish on Steam, disclose AI-generated content in Steam's content survey.
Make your game. Grow your game.
Even if it is built in another engine.
Free to download for macOS (Apple silicon) and Windows.