API Reference > imodeljs-backend > Elements > RenderMaterialElement.Params > specular specular specular: undefined | number If defined, apply this surface specular reflectivity; if undefined, defaults to 0.0. NOTE: The actual JSON allows a HasSpecular property to be true and the specular value itself undefined, in which case the value 0.4 would be used. This API does not allow this case. Defined in core/backend/src/Material.ts Line 122 Last Updated: 13 June, 2024