Hand-painted and stylised texturing

Hand-painted texturing paints a surface's form, light and material directly into its colour texture, instead of relying on the renderer to work them out from physically based rendering maps. It is the classic look of stylised games such as World of Warcraft. Blizzard's Fanny Vergne describes the goal as creating "the illusion of materials by painting in the way light interacts with the surface" (80 Level: The Strings of Environment Design).

"Stylised" is broader than "hand-painted": a stylised asset can also use PBR materials with exaggerated shapes and colours. This page covers the painting skills that both share.

#What makes a texture "hand-painted"

In a realistic PBR texture, the base colour holds only the surface colour, and light comes from the engine. In a hand-painted texture, the colour map also holds:

• Form shading: edges lit, cavities darkened.
• Light direction: usually from above. On Polycount, LokiDokie notes that "usually hand painted models are painted with top down lighting", while adding that it is a matter of choice (Polycount: I need c&c for my works).
• Material cues: highlights on metal, grain on wood, painted with brush strokes rather than measured.

Some hand-painted games render these textures unlit. Jamie Read describes his diorama below as "1050 tris, 1024 diffuse, unlit" (Sketchfab: Seagull Shack): every bit of light you see is painted.

#Value

Before colour, a hand-painted texture has to read in greyscale. See value and visual hierarchy and readability.

• Keep textures neutral for reuse. Vergne: "it is very important to keep the values of your textures neutral", so that one texture works in many places, and "use your lighting and scene ambience to do the heavy lifting of the environment mood" (80 Level: The Strings of Environment Design).
• Use gradients to guide the eye. In a Polycount critique, Brian "Panda" Choi recommends subtle value gradients to draw attention to focal points (Polycount: I need c&c for my works).
• Do not shade with black and white. Choi pointed out that the artist was lighting by "just adding more black or white to a lot of the texture" (Polycount: I need c&c for my works). That flattens colour; shift hue instead.

#Hue shifts

When value changes, hue should change too. Choi: "Objects shift hues when values change", and "dark areas get colder in color temperature (bluer)" under warm light (Polycount: I need c&c for my works). Vergne's colour advice works at scene level: make "your ambient color and the dominant color of your lights complementary or close to each other", and keep saturation and brightness under control even in a colourful palette (80 Level: The Strings of Environment Design).

#Workflows and tools

There is no single hand-painted workflow. Common ones:

1. Paint flat in 2D. Lay out UVs, paint the texture in Photoshop, Krita or similar, check on the model, repeat.
2. Paint on the model. Tools such as 3DCoat and 3DCoatTextura advertise "hand-painted and PBR textures" with brushes, smart materials and layers (3dcoat.com: 3DCoat); Substance 3D Painter is also widely used, as in the diorama above. Mari supports "procedural to hand-painted textures" too, though it is mainly a film tool (foundry.com: Mari).
3. Sculpt, bake, then paint over. Sculpt shapes, bake them to get AO, curvature and a lit base, then paint on top. Vergne uses ZBrush "on the most detailed textures or to create quick basic shapes for my tiling textures" (80 Level: The Strings of Environment Design). Yulong Huang's stylised tool kit was sculpted in ZBrush and textured in Painter, with hand-painted masks to break up brush strokes (80 Level: How to Make Tool Kit With History Using…).

Hand-painted textures are still used as tileables, trims and atlases; the mapping rules are the same. See ways to texture an environment.

#Further reading and watching