Mural3 is a keystone and grid-warp tool for multi-projector installations, video walls, and immersive art.Mural3 (The Mural) helps you align and warp Unity camera output for real-world projection surfaces. Whether you are building a museum installation, a stage show, a themed attraction, or a multi-display video wall, Mural3 gives you interactive keystone correction and optional freeform grid warping directly in Play mode.Each projection region has an Input side (source rectangle on your render) and an Output side (placement on the physical surface). Drag four corners for classic keystone correction, or switch to Warp mode and sculpt curved surfaces with a control grid and Freeform editing. Multiple regions can overlap with automatic edge blending for seamless multi-projector composites.The package is fully customizable for your project workflow:Per-region settings — Flat keystone-only or full grid warp, independently for each projectionRuntime GUI — Toggle with a hotkey (default M); add, remove, and switch regions without leaving Play modeInspector options — Edge blend, projector simulation preview, mask texture, colors, save path, and moreJSON persistence — Save and load entire setups; legacy v3.1 configs migrate automaticallyOptional mask texture — Restrict projection to arbitrary shapesExamples sample — Import a ready-made scene from Package Manager to learn the workflow quicklyMural3 is built for installation art, live events, architectural projection, exhibitions, VR/AR companion displays, and any URP project that needs in-engine projection mapping rather than a separate desktop tool chain.Requirements: Unity 6 (6000.0 LTS recommended), Universal Render Pipeline 17+, Input System.Core mappingMulti-projection region management (add / remove / cycle regions at runtime)Input / Output editing modes — place source rectangles (OBB) and correct output placement separatelyFour-corner Keystone correction per region (classic trapezoid / perspective fix)Flat and Warp modes per region — choose simple keystone or advanced deformationFreeform grid warp on output surfaces — control grid (1–8 cells), mesh subdivision (1–32), Bilinear or Catmull-Rom interpolationFoldover detection — invalid self-intersecting deformations are rejected with a runtime warningOn-screen warp grid overlay with curved visualizationRendering (URP)Mapper Scriptable Renderer Feature integrated with URP Render Graph (RecordRenderGraph)Applies warped camera output after post-processingGPU mesh generation via compute buffers; custom Hidden/Mural3/Mapper shaderOptional projection mask texture supportMulti-projector blendingDistance-based edge blending in overlapping input UV regionsAdditive simulate projector mode for single-display preview of multi-projector overlapEdge-blend weight visualization (heatmap)Persistence & compatibilityJSON save/load (schema v2) with automatic migration from legacy four-corner formatEnvironment-variable support in save pathsDistribution & samplesLocal UPM package (jp.nobnak.mural3) with Package Manager Examples sampleDependencies resolved via OpenUPM (jp.nobnak.gist2, jp.nobnak.llgraphics)Platform notesTested on Unity 6000.0.78f1 with URP 17.0.4Render Graph Compatibility Mode must be disabledInput shape is rectangular (OBB) on the input side; Freeform warp applies to output onlyDevelopment process: AI-assisted tools were used to support feature expansion and documentation generation. All AI-assisted output was reviewed, tested, and corrected by the author in Unity before release. Human verification covered runtime behavior, warp accuracy, URP rendering, edge blending, save/load, and compatibility with the target Unity version.In short: AI helped draft and extend features and docs; humans performed validation and fixes to ensure the shipped package works as intended.
