API Reference > imodeljs-common > Rendering > RenderMaterial.Params > alpha alpha Accessor A value from 0.0 (fully-transparent) to 1.0 (fully-opaque) controlling the transparency of surfaces to which this material is applied; or undefined if this material does not override surface transparency. get: number | undefined Returns - number | undefined Setter A value from 0.0 (fully-transparent) to 1.0 (fully-opaque) controlling the transparency of surfaces to which this material is applied; or undefined if this material does not override surface transparency. set(alpha: number | undefined): void Parameter Type Description alpha number | undefined Returns - void Defined in core/common/src/RenderMaterial.ts Line 74 Last Updated: 15 June, 2021