Description

The cel shading used is a layered model: two layers for basic color and one layer for highlight, which is commonly used in anime. The light-shade boundaries can be specified by the custom threshold. The global brightness and shade falloff can be specified accordingly.

The outline drawing covers the features of silhouettes, creases, and boundaries. In the legacy version 1, the three types of outlines are separately extracted. In version 2, creases and general silhouettes are covered by one extraction method; silhouettes with suggestive contour is an extension which is suitable for characters.

Procedural and texture hatching are also supported. The hatching density, direction, threshold, and pattern can be specified.

Generally, it can be compatible with common shading materials used in the photo-realistic rendering, that is, no specific texture or extra material is necessary. The style rendering can be switched by the custom stencil values of the target meshes.

Brief tutorial:

1. Project settings -> Engine -> Rendering -> Postprocessing -> Custom depth-stencil pass, choose Enabled with Stencil.

2. Add mesh objects and set light sources.

3. Add a post process volume, then Rendering features -> Post Process Material -> Array + -> Asset Reference, drag the material/instance into the blank.

4. For each mesh object, set the custom stencil value, default value 7 ( = 1 + 2 + 4) for enabling all basic effects. For a character, setting 15 for enabling all effects.

5. Face light supplement: just drag the BP_FaceLight into the scene, and specify the default skeletal mesh variable to the target character.

6. For auto global light intensity estimation, please refer to the sample BP_Light_Intensity_Estimation.

Technical Details

Materials:

Version 1 (V1, legacy) – 4 Postprocess (PP) materials

Version 2 (V2) – 2 PP materials

Version 3 (V3) – Add 4 basepass materials (templates) for mobile cel shading and 1 PP material for outline drawing

Material instance:

V1

4 anime/manga instances with and without hatching

V2

For shading, line drawing, and hatching

Material functions:

V1

1. Cel anime & manga shading

2. Suggestive contour, crease, and boundary

3. Helpers

V2

1. Cel shading

2. Outline

3. Suggestive contour

4. Helpers

V3

Additional cel shading, line drawing, and helpers for mobile

Blueprints:

1. Sample of global light intensity estimation

2. Spot light for face light supplement

V3

For getting main-light info.

Tested platform:

Windows

Hints:

To switch on the expected effect, the custom stencil need to be set to the sum of the necessary mask values for each object.

In V2, the default stencil masks are

Cel shading = 1

Outline = 2

Hatching = 4

Silhouette (suggestive contours) = 8

Commonly, setting custom stencil = 7 for each object is OK. For a character, 15 is recommended to enable the suggestive contour for better details conveying.

The stencil masks can also be customized, if the default values are used for other things and the rules are commanded.

For using mobile, please first drag BP_MainLightInfo into the scene.

Limitations:

1. Only support 1 main directional light

2. Outlines may not always work as same good quality as the PC version for arbitrary geometries.

Supported Engine Versions

4.21 – 4.27, 5.0 – 5.3