Anvil CSG

Anvil CSG is a four-view brush level editor for Unity 6. Fast CSG tools, editable maps, optimized builds with occlusion culling, BSP lightmap UVs, Bakery and Amplify Shader Editor support.

Level Editing

• Four-view workspace with Top, Front, Side and Perspective views
• Convex brush modelling with configurable grid snapping and Smooth Snap
• Box, wedge, cylinder, spike, arch, door arch, arc, curved hallway and stair primitives
• Face, edge and vertex selection and editing
• Clip, Carve, Hollow, Bevel, Curvature, Array and Cell Fracture tools
• Brush grouping with nested groups, Build Sections, View Filters and build flags
• Local Build Areas for working on part of a larger map
• Blueprint reference images with scale calibration in orthographic views
• Copy and paste with placement preview, Paste in Place and Select Similar
• Configurable perspective and surface grids
• Customizable hotkeys

Materials and UVs

• Paint regular Unity Materials directly onto individual faces
• Box-projected texture mapping
• Texture scale, offset, rotation, fit and alignment controls
• Texture locking while transforming geometry
• Material and UV sampling between surfaces
• Multi-brush and per-face UV editing
• Amplify Shader Editor material support
• Amplify Shader Editor is an optional third-party asset and is not included

Environment Tools

• Editable terrain with material layers
• Decal placement with live preview, corner wrapping and surface sliding
• Light creation and editing
• Reflection-probe tools
• Anvil light-probe volumes
• Prefab placement and generated-map support
• Test Physics with a physics hand, results applied to the level

Build and Validation

• Check Map validation with safe repair tools
• Recovery snapshots for the editable source map
• Separate editable source map and generated output
• Level Optimization: merged meshes, flat-face merging, simplified and box colliders
• Optional hidden-face removal, occlusion culling and GPU instancing
• Per-brush Unity layers and Keep Separate, Never Remove Faces and Non Static flags
• Generated decals, prefabs, lighting data and supported probes
• Generated maps can be loaded into other Unity scenes
• Rebuild generated output whenever the editable source changes
• Quick Export to OBJ with materials and textures

Lightmapping

• Anvil BSP UV2 unwrap designed for architectural brush geometry, including curved and edited brushes
• Xatlas (native library included for Windows and Linux editors), Unity Default and Unity XAtlas options
• Separate UV2 and lightmap settings for brushes and prefabs
• Per-face and per-brush lightmap density
• Configurable texel density, padding and lightmap page limits
• UV2 validation before light baking
• Unity lightmapper support
• Full Bakery workflow integration when Bakery is installed
• Bakery UV generation, lights and lighting workflow support
• Bakery is an optional third-party asset and is not included

Compatibility

• Unity 6 support tested from Unity 6.0 through Unity 6.7
• Built-in Render Pipeline support
• Universal Render Pipeline support
• HDRP is not currently supported
• Bakery support follows Bakery's own supported Unity versions
• Editor-only level-design workflow
• Generated maps can be included in regular Unity builds

Build complete brush-based levels without leaving Unity. Anvil CSG brings the familiar workflow of classic editors such as Hammer and TrenchBroom directly into the Unity Editor, with dedicated top, front, side and perspective views.

Create rooms, corridors, stairs, arches and complete environments using editable brushes. Work by brush, face, edge or vertex. Cut openings with Clip and Carve, break walls apart with Cell Fracture, paint materials directly onto surfaces and adjust texture alignment without returning to a 3D modelling application.

Your source map always remains editable. Build Map creates a separate optimized version containing merged render meshes, collision, decals, UV2 and supported probe data. Change the original map and rebuild it whenever needed. Built maps can also be placed in other scenes.

Level Optimization cuts triangles, batches and colliders automatically. It merges brushes and flat faces, simplifies collision, can remove faces the player never sees, bakes occlusion culling and uses GPU instancing for repeated prefabs. Prefer to optimize by hand? Per-brush Unity layers and the Keep Separate, Never Remove Faces and Non Static flags give you full control.

Decals follow the surface, wrap around corners and curves, and can be placed with a live preview, sized by dragging and slid across walls.

Test Physics lets you drop, push and throw objects in their own physics scene, then apply the result to your level.

Anvil does not lock your project into one material or lighting workflow. Regular Unity materials and materials created with Amplify Shader Editor can be painted onto brushes and preserved in the generated map.

For Unity lighting, Anvil includes its own BSP-style UV2 unwrap designed specifically for architectural brush geometry, with consistent texel density and fewer wasted lightmap charts, even on curved and edited brushes. Xatlas, Unity Default and Unity XAtlas workflows are also available, and prefabs get their own lightmap settings.

Bakery is fully supported when installed. Anvil can prepare the generated map for Bakery, use Bakery UV generation and work with Bakery lights, sky lighting and its lightmap workflow.

Check Map finds geometry, material, UV and build problems before the final map is generated. Safe repairs and Recovery snapshots help protect the editable map while working on larger projects.

Built for large maps: thousands of brushes stay smooth to select, move, copy and paste.

Anvil CSG is suitable for FPS levels, immersive sims, dungeon crawlers, arenas and other projects built around architectural environments.

Supports Unity 6.0 to 6.7, Built-in Render Pipeline and Universal Render Pipeline. HDRP is not currently supported.

Special thanks to the Anvil CSG beta testers who helped shape this release by reporting bugs, testing workflows and suggesting improvements: Bytefennec, Cocobear, KeithG, MCL15, PapaFrank, Alex, Andre Blunt, BlakVice, Eric, Gzke, Huitistbro, JustinM, King Lmao, Port and Zorro.

Documentation

Discord