In Level & terrain generation, Marble (World Labs) ranks #1 and Ludus AI ranks #3. No independent quality tests found. Ranked on game-dev fit: commercial use restricted; Unity, Unreal integrations; API.
Commercial use: Ludus AI: not stated by vendor terms. Marble (World Labs): restricted (see notes) terms.
Free plan: Ludus AI: free trial or credits only (14-day Pro trial; free account has no credits) pricing. Marble (World Labs): free plan (Up to 4 world generations) pricing.
API and MCP: Ludus AI: API not stated by vendor, MCP not stated by vendor. Marble (World Labs): public API, MCP not stated by vendor.
Engine integrations stated by the vendor: Ludus AI: Unreal. Marble (World Labs): Unity, Unreal.
Unreal teams wanting an in-editor agent for Blueprints, C++ and levels
Explorable 3D environments and flythrough shots
What it does
AI toolkit that runs inside the Unreal Engine editor: an agent that understands your project's Blueprints, C++, assets and levels and can answer questions and make edits.
Generates persistent 3D worlds from text, images, video, 360° panoramas or blocked-out 3D layouts. Exports Gaussian splats and GLB meshes, and records camera flythrough videos.
Verdict
For Unreal devs who want a project-aware assistant in the editor; it has no free credits beyond a 14-day trial, and its output licence is unverified.
For blocking out explorable environments or flythrough shots; exports go to Unity/Unreal via Gaussian-splat plugins, and commercial rights are listed on Pro.
Tasks●
Coding assistants, Level & terrain generation
Level & terrain generation, Trailers & marketing
Engines●
Unreal
Unity, Unreal
Free plan●
Free trial or credits only 14-day Pro trial; free account has no credits
Free plan Up to 4 world generations
Pricing
14-day Pro trial. Pro $25/month, Studio $80/month, Ultimate $180/month (plus VAT; yearly billing discounted). Free account has no credits. source
Free $0/month (7,000 credits, up to 4 world generations). Standard US$20/month (20,000 credits), Pro US$35/month (40,000 credits; commercial rights) and Max US$95/month (120,000 credits). Top-up credits from US$5 on Standard and above. Enterprise custom. The World API is billed separately. source
Export formats●
Edits made inside the Unreal project
SPZ and PLY Gaussian splats; GLB collider and high-quality meshes source
Commercial use●
Commercial use: not stated by vendor Ownership/commercial terms for generated output: unverified. source
Restricted (see notes) Billing docs list "commercial rights to generated worlds" on the Pro plan. Commercial terms for Free and Standard: unverified. source
Rows marked ● differ between the two tools. Licence badges: green = commercial use allowed (including any free plan or trial), amber = paid plans only, restricted, or allowed but with no free plan, red = not allowed, grey = not stated by vendor or not applicable. Read the vendor's current terms before you ship.