For those who don’t know the tool: Light Painter is a Blender add-on for lighting lookdev that paints onto a light texture in Cycles using Spot or Area lights, right in the viewport.
Setup: Cycles or nothing
Light Painter by ShaderError depends on Cycles light texture nodes, so it requires Cycles as the render engine. It does not support Eevee for this workflow. The baseline is Blender 3.6 through 5.1, and tCycles as the render engine and GPL as the license. Before you get excited and start scribbling highlights onto your hero asset, there is a short checklist that matters. You need a Spot Light or an Area Light, since the tool only works with those two light types. Point and Sun lights do not apply here, because the workflow relies on directional texture projection.
For sharper painting while you work, keeping the light size small helps. Spot Light uses a small Radius value and a Spot Size under 160 degrees to reduce distortion. Area Light uses scene scale dependent Size and a fairly low Spread value while painting. You can soften things later by changing Radius or Spread, but the painting stage favors crisp edges so you can read what you are doing.
The docs also recommend enabling GPU Compute for performance, since the tool relies heavily on shader computation. CPU rendering still works, but GPU is expected to be faster.
Painting on lights, not on meshes
The core idea is simple: you paint into a texture image that drives the light, and the tool previews the result in the viewport while you paint. You choose the target light in a panel, pick a texture resolution, and run a reset action that initializes the node setup. Then you paint using tools that include a brush and a gradient tool.
Light Painter stores the paint in a light texture image, with selectable resolutions from 512 pixels up to 4096 pixels. Higher resolution gives finer detail at the cost of more memory and slower interaction.
There is also a surface scoping system that controls what receives paint. You can paint on all meshes, a single object, or a collection. Separately, there is a skip list for objects that should behave as transparent for the painting depth pass, like glass windows, translucent curtains, fog and dust volume boxes, wireframe grids, and objects used for volumetric effects. If a see-through object blocks your strokes, it needs to be marked there.
Layers, masks, and the temp EXR stash
Light Painter includes a Photoshop style layer stack per light. Layers have blend modes, opacity, visibility, and transforms, and they composite from bottom to top. Blend modes listed in the docs include Mix, Multiply, Screen, Add, Subtract, Overlay, and Soft Light.
Each layer creates a Blender image datablock to hold pixel data. The layer system also writes temporary files to disk in the OpenEXR format to support undo, persistence, and compositing. These temporary files are cleaned up automatically when the add-on is disabled or when Blender closes, and layer metadata such as names, blend modes, order, and transforms is saved inside the blend file.
Layer transforms are non-destructive in light UV space, with offset, rotation, scale, and a pivot. The docs list shortcut gestures while the brush or gradient tool is active for moving, rotating, and scaling the active layer.
Selections add another control lever. You can build a mask to restrict painting so areas outside the selection are protected. The selection tool supports rectangle, polygon, lasso, and brush shapes, plus modes like add, subtract, and intersect. Expect to use this when you want to localize a fill or protect a face from accidental spill while you dial in a rim.
About that spill: the docs warn about light bleed beyond the painted region when the light source has a physical size. Blender can spread light beyond the texture boundary and into shadowed areas, and the current version does not compensate for that during painting.
Camera space vs light space
There are two paint spaces. In camera space, the paint is designed to match what you see on screen, with brush falloff mapping one-to-one with the viewport result. In light space, the brush math and gradient blending happen in the light texture space, while the brush centre and gradient endpoints come from the viewport, which can look distorted in the viewport depending on angle and distance.
Light space comes with two projection approaches for mapping the cursor. Raycast traces against geometry each frame and falls back when the cursor moves off surfaces. Plane establishes a paint plane on the first click, then projects subsequent cursor positions onto that plane. The gradient tool always uses raycast in light space.
This split is practcial. Camera space supports quick art direction because what you see is what you paint. Light space supports behavior that follows the light texture space more directly, and the docs describe it as a fallback for edge cases where camera space painting fails to cover some texels, such as steep angles or complex shadow boundaries.
Some studios will end up using both in the same shot. Start in camera space for broad strokes, switch to light space for the annoying bits, and remember that the annoying bits always find you in the final.
Preview and troubleshooting
The add-on includes a real-time overlay preview system. One mode previews only what is currently being drawn. Another mode overlays the full light texture and mask across the viewport and marks unpaintable areas in red, so you can see where the light reaches and where it is blocked.
There is also a preview option to show raw paint colour versus a falloff preview that includes rendering factors like distance attenuation and exposure. A light blur option attempts to mimic how Blender spreads the light based on the physical size of the source, with a multiplier to scale the effect.
If the result looks broken, reset the operator that rebuilds the shader node setup and resets layers. Changing light size can reset layers because the texture proportion ties to light size, and the docs recommend undo if the size change was accidental.
Advanced settings in the docs cover near and far clip for the light frustum, a surface bias for shadow acne, softness and bleed reduction controls, and internal capture resolutions.
Pricing and licensing
Light Painter is sold on Superhive in multiple tiers. LightPainter Lite is listed at $12. LightPainter for individuals is listed $36. LightPainter Indie for up to 3 people is listed at $80. LightPainter Full for up to 14 people is listed at $350. LightPainter Studio for 15 or more people is listed at $750. Currently there is a promotion that halves the prizes, no idea how long that goes.
As always, test any new tool and workflow in a controlled scene before it touches production assets, especially anything that rewires nodes, writes temp files, or changes how your lgiht setup evaluates across machines.
// Product page, pricing tiers, compatibility, license
https://superhivemarket.com/products/light-painter
