API Reference > imodeljs-backend > iModels > ExportPartGraphicsOptions > decimationTol decimationTol decimationTol: undefined | number Max distance between mesh vertices for them to be collapsed. Meshes stored in GeometryStreams are unaffected by StrokeOptions settings. If decimationTol is undefined, they are output from exportGraphics without any reduction in quality and can be too detailed for some uses. However, decimation is a destructive operation that can introduce gaps and other visual anomalies so it is important to choose an appropriate setting for your use case. Defined in core/backend/src/ExportGraphics.ts Line 234 Last Updated: 12 June, 2024