KLayout’s 2.5D (often written “25D”) view is a visualization mode that augments planar GDS/OASIS layout layers with a height dimension—letting users inspect and present topography, stackups, and thickness-aware geometries without needing a full 3D CAD tool. It’s especially useful for photonics, MEMS, semiconductor process visualization, and PCB/packaging cross-sections where layer thicknesses or etch depths matter.
For extremely large layouts (>10 GB GDSII), create a quick 25D view by first using Hierarchy > Flatten on selected cells, then reduce detail with Edit > Selection > Convert to polygons with a tolerance of 0.01 µm. klayout 25d view
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