Klayout 25d View May 2026

If your polygons just look like flat colored pancakes even in perspective mode, check the "Sidewall" thickness. Without sidewalls, an extruded polygon is invisible when viewed from the side. Set "Sidewall width" to at least 1 pixel.

KLayout provides a simple lighting model: ambient, diffuse, and specular. Under View Settings > 2.5D, you can adjust light direction, intensity, and shadow softness. For debugging, disable shadows for performance.

KLayout operates primarily as a GDSII, OASIS, and DXF file viewer. In standard operation, it renders layout data as flat, 2D polygons on distinct layers. However, modern semiconductor processes involve complex vertical topologies. The "2.5D View" (often referred to as the "3D View" or "Cross-Section View" within the software) bridges the gap between flat 2D plans and physical 3D realization.

Note on Terminology: In the context of KLayout, "2.5D" refers to the ability to render 3D geometry based on 2D polygons extruded by defined heights, often utilized through the Cross-Section View and the 3D Viewer.

If you have been using KLayout purely as a 2D layout viewer, you are only tapping into half its potential. The 25D view transforms your flat colored polygons into an intuitive, extruded landscape where vertical conflicts, missing layers, and structural anomalies leap out instantly.

It is not a full 3D simulator – and that is perfectly fine. For tape-out checks, MEMS topology inspection, and even client presentations, the 2.5D perspective offers the best trade-off between speed, clarity, and physical insight. With a few minutes of layer height assignment, you can see your design the way it will exist on silicon: as a three-dimensional object, not just a geometric abstraction.

So open KLayout, enable OpenGL, assign a height to your metal3 layer, and tilt that view. Your next layout bug – or your next elegant solution – will reveal itself in the third dimension.

About the author: This article is written for IC, MEMS, and PCB layout professionals using KLayout. For further reading, consult the official KLayout documentation under “2.5D View” and explore the user forum threads on setting realistic layer heights for your specific technology node. klayout 25d view

The 2.5D View in KLayout is a powerful visualization tool that extrudes 2D layout layers into a 3D-like perspective. It is primarily used to inspect material stacks and vertical layer relationships, which can be difficult to visualize in a standard flat view. Core Requirements & Setup

OpenGL Support: The 2.5D view is only available if your KLayout version was compiled with OpenGL support.

2.5D Scripting: To use the tool, you must create a script that defines how the layers are stacked and extruded. These scripts use a variant of the DRC (Design Rule Check) language.

Performance: The practical performance limit is currently around 100,000 polygons. How to Use the 2.5D View

Create a New Script: Go to Tools > 2.5d View > New 2.5d Script. This opens a new script template in the macro editor.

Define Extrusions: Use specific DRC functions to build your stack: z(layer, [options]): Extrudes a specific layer.

zz([options]) block : Groups multiple z statements to create complex 3D material geometries. If your polygons just look like flat colored

Run the View: Click the Run button in the macro editor or select your script from the Tools > 2.5d View menu.

Sync with Layout: The 2.5D window displays the section currently visible in your main layout view. If you close the window, you can reopen it via Tools > 2.5d View > Open Window. Navigation & Controls

Rotation: Drag with the right mouse button to change the viewing angle (azimuth and elevation).

Movement: Drag with the middle mouse button to pan the view or use the arrow keys.

Zooming: Use the mouse wheel to move the camera forward/backward, or Ctrl + Mouse Wheel to magnify the layout.

Exaggerate Height: Use the Z-axis zoom slider (on the right) to exaggerate height variations, which is helpful if the real height profile is too flat to see clearly. Visual Customization

Colors & Visibility: The 2.5D view inherits colors directly from your active KLayout Layer Properties. If you hide a layer or change its fill color in the main window, the 2.5D view updates accordingly. KLayout provides a simple lighting model: ambient, diffuse,

Net Tracing: While primarily for geometry, it is possible to export a specific net (e.g., from the Net Tracer) to visualize its path through different vertical layers. Colors in the 2.5d View - KLayout Layout Viewer And Editor

In very dense designs with overlapping transparent layers, Z-fighting (flickering textures when two surfaces occupy the same plane) can occur. This is a common OpenGL artifact but can be distracting when trying to inspect fine details.

KLayout’s 25D feature requires a few setup steps. It is not enabled by default in minimal installations due to hardware acceleration dependencies.

Before diving into KLayout, we must clarify the terminology. In computer graphics, 3D implies full six-degree-of-freedom navigation (x, y, z translation, plus roll, pitch, yaw). 2D offers only x and y.

2.5D (or 25D) is a compromise. It simulates depth by extruding 2D polygons vertically and allowing perspective or orthographic rotation, but typically restricts navigation to a limited range (e.g., tilting the view, but not going "under" the substrate). The model remains fundamentally 2D geometry with assigned layer heights and materials.

In KLayout’s implementation, the 25D view:

This makes the 25D view exceptionally fast—almost as responsive as 2D—while conveying 80% of the spatial insight of a full 3D engine.

Navigate to the menu: View > Panels > 3D View. This will dock a new window pane, usually on the right or bottom of your screen. Initially, it might just look like a black box or a flat green square.