Light Reference – Free 3D Lighting Reference Tool for Drawing
An interactive lighting reference website for 2D artists, illustrators, and digital painters.
Create a light and shadow reference for your next drawing. Move the light, adjust its color and softness, and study spheres, cubes, and cylinders. Import your own OBJ model for portrait or character studies, then download a PNG to keep beside your canvas.
Use the 3D lighting tool below, or try 2D Relight to explore lighting on an existing drawing or painting.
Use the lighting simulator for drawing practice
Start with one shape and one light. Move the light above, below, and to the side of the subject. Compare the lit planes, the shadow on the form, and the cast shadow before changing another setting.
- Cube lighting and shadow reference: practice flat planes and follow the cast shadow as the light moves.
- Face and portrait lighting reference: import your own head model and compare front, three-quarter, and rim lighting.
- Soft vs. hard shadow studies: compare sharp shadow edges with softer transitions.
- How to create a lighting reference for drawing: follow the quick start and save a reference image.
Start with a cube lighting reference or a soft-lit sphere reference. Each link opens the tool with the study settings ready to use.
For an existing drawing or painting, try 2D Relight to experiment with lighting on your uploaded image.
How This Tool Works (TL;DR)
The scene simulates a key light you can place with Azimuth (horizontal angle) and Elevation (vertical angle), then refine with Light Distance, Beam Angle (spread), and Softness (shadow edge quality). A Fill Level adds ambient lift for the shadows. You can also move and rotate each shape to study how planes react. Use the Presets dropdown to jump to common setups, Fullscreen for a bigger viewport, Copy Link to share your exact settings, and Download PNG to save a frame.
Want the full breakdown with screenshots? Read the complete guide →
Assumptions
- Single spot light aimed at the origin; shadow sharpness influenced by softness and beam angle.
- Optional Auto-Compensate for Distance boosts intensity ~with inverse-square so brightness stays comparable as you move the light, while preserving falloff and shadow behavior.
- Ambient/hemi Fill Level lifts shadows uniformly; no GI, subsurface scattering, or textured roughness maps.
- Highlights/shadows come from surface normals on basic geometry (sphere, cube, cylinder).
- Grid plane is purely for spatial context; object scale is fixed for consistent comparisons.
Controls at a Glance
- Azimuth/Elevation (°): place the key light around and above/below your subject.
- Light Distance: move the light in/out; farther lights naturally look dimmer (inverse-square).
- Auto-Compensate for Distance: maintain comparable subject brightness while exploring distance changes.
- Beam Angle (°): narrow = punchier, tighter hot-spot; wide = broader, more even coverage.
- Softness: Hard for crisp shadow edges, Soft for wider penumbra and gentler speculars.
- Fill Level: ambient lift for shadows (0–0.6) without moving the key.
- Shape Controls: position (POSX/Y/Z) and rotation (ROTX/Y/Z in radians) per shape; neutral gray is best for study.
- Presets: one-click starting points (3/4 Key, Rim/Back, Beauty Soft, Product Front, etc.).
- Utilities: Hide Grid, Fullscreen, Copy Link, Download PNG, Reset.
Method (Simplified)
- Convert azimuth/elevation to radians and compute a light position at radius
r(the Light Distance) on a sphere. - Aim a SpotLight at the origin; set
anglefrom Beam Angle andpenumbra/shadow radiusfrom Softness. - If auto-comp is enabled, scale light intensity by
(r / rref)²to offset inverse-square loss. - Evaluate diffuse/specular using surface normals; add ambient/hemi fill from Fill Level.
Example Setups
3/4 Portrait (Hard): Az 45°, El 30°, Dist 6, Beam 35°, Softness Hard, Fill 0.20. Clear form, crisp terminator.
3/4 Portrait (Soft): Az 45°, El 30°, Dist 4, Beam 60°, Softness Soft, Fill 0.30. Flattering shadows and broader highlights.
Rim Back: Az 150°, El 25°, Dist 7, Beam 20°, Softness Hard, Fill 0.10. Bright edge, strong separation.
Beauty Soft: Az 0°, El 60°, Dist 4, Beam 70°, Softness Soft, Fill 0.50. Low contrast, gentle speculars.
Behind the Scenes: How This Light Reference Tool Was Built
In this video, I walk through how the Light Reference web app came together—from the first prototype to the current version you’re using now. If you’re curious about the tech behind the tool or you’re a developer/artist who wants to build something similar, this is a good place to start.
You’ll see how the app:
- Handles lighting controls in a way that feels natural.
- Balances visual quality with performance so it can run in the browser.
- Is designed specifically for artists who need quick, repeatable lighting studies.
Watch the breakdown, then jump back into the app with a better sense of what’s happening under the hood—and how you can fold it into your own practice or projects.
Video: A walkthrough of how the Light Reference app was designed and built.