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Engine features

Choose a material aspect or rendering capability, learn its public API, and explore it in a live glTF sample. These features belong to the engine and shared shader modules; glTF is one way to author and exchange them. Each page describes glTF core or extension support separately.

Surface appearance​

  • Metallic and rough surfaces — Base color, metallic response, and roughness describe surfaces ranging from matte dielectrics to polished metals.

  • Unlit surfaces — Unlit surfaces preserve their surface color without evaluating scene lighting, useful for signs, diagrams, and baked artwork.

  • Emissive surfaces — Emission makes a surface contribute its own visible radiance, including values above the display white level.

  • Specular reflection — Specular reflection controls the strength and tint of dielectric highlights independently of the base diffuse color.

  • Index of refraction — Index of refraction controls the optical contrast at a dielectric boundary and influences reflection and transmitted light.

  • Transmission, volume, and dispersion — Transparent materials transmit light through a surface; thickness, absorption, and wavelength separation describe glass and colored volumes.

  • Clearcoat — Clearcoat adds a secondary glossy layer over a base surface, useful for varnish, lacquer, and automotive paint.

  • Sheen — Sheen adds a soft grazing-angle response for fabric, velvet, and other surfaces with fine fibers.

  • Iridescence — Thin-film interference produces view-dependent colors, useful for coated glass, soap films, and decorative finishes.

  • Anisotropic reflection — Anisotropic reflection stretches highlights along a surface direction, useful for brushed metal and directional surface finishes.

  • Normal and bump mapping — Normal and height textures add apparent fine surface detail without increasing mesh tessellation.

  • Diffuse transmission and scattering — Diffuse transmission lets light emerge from the opposite side of a thin or scattering surface, useful for leaves, paper, and translucent ceramics.

  • Texture coordinates and transforms — Independent texture coordinate sets and transforms let each surface map use its own placement, rotation, and scale.

  • Base color

  • Opacity and cutouts

  • Double-sided surfaces

  • Ambient occlusion

  • Normal mapping

  • Emissive strength

  • Volume absorption

  • Dispersion

Scenegraph capabilities​

The Scenegraphs guide is the canonical index for animation, skins, morph targets, interactivity, physics, physical joints, billboards, scene lights, and spatial audio. These engine runtimes work with imported and programmatically constructed scenes.

  • Material variants — Material variants switch authored surface appearances while preserving the scene hierarchy and model identities.

  • Animation and deformation — Animation combines clip playback, skeletal deformation, and morph targets to bring characters and scene objects to life.

  • Mesh instancing — Instancing draws many placements of shared geometry with one draw per compatible primitive instead of duplicating models.

  • Punctual lighting — Directional, point, and spot lights provide explicit scene illumination with controllable direction, intensity, and color.

  • Compressed geometry and textures — Compressed geometry and textures reduce asset transfer size and can reduce GPU texture storage when the device supports the resulting format.

  • Scene visibility — Hide a scene subtree while preserving its hierarchy and resources for later reuse.

  • Animated crowds and levels of detail — Render independently animated characters with shared GPU geometry and select mesh detail by projected screen size.

glTF integration reference​

The format-focused documentation remains the source for import contracts and support details: