VTK (.vtk, Visualization Toolkit) is a file format for 3D scientific data, developed for the open-source Visualization Toolkit library. The legacy .vtk format stores geometry and data in ASCII or binary. The XML-based .vtp (PolyData) variant is the modern replacement with better structure and extensibility.

What is the difference between .vtk and .vtp?

.vtk is the legacy format with a simple header-based structure. .vtp is the XML-based modern format (VTK XML PolyData), supporting structured/unstructured grids, multiple data arrays and better metadata. Both are supported by the viewer.

Are my VTK files uploaded?

No. Files you open from your device stay on your device and are rendered locally with WebGL. Only the public sample is requested from the server.

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VTK Viewer

Free online VTK viewer. Open and preview scientific visualization files (.vtk, .vtp) directly in your browser — no upload, no 3D software.

.vtk.vtp

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About this file format

VTK (.vtk, Visualization Toolkit), developed by Kitware, is the standard file format for scientific 3D visualization. The legacy .vtk format uses a simple ASCII or binary structure with headers for points, cells and data arrays. The modern XML-based variants (.vtp for PolyData, .vtu for UnstructuredGrid, etc.) offer better structure and extensibility. VTK is widely used in computational fluid dynamics (CFD), finite element analysis (FEA), medical imaging and geospatial visualization.

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