OpenVSP: Parametric Aircraft Geometry Guide

Short answer

OpenVSP (Open Vehicle Sketch Pad) is an open-source parametric aircraft geometry tool originally developed by NASA for conceptual aircraft design and rapid aerodynamic evaluation. Released under the NASA Open Source Agreement (NOSA v1.3), OpenVSP generates 3D vehicle geometries from standard aerospace parameters, performs integrated vortex-lattice and panel aerodynamic calculations via VSPAERO, and exports watertight meshes for computational fluid dynamics (CFD).

Definition and scope

OpenVSP bridges the gap between early conceptual sketches and production Computer-Aided Design (CAD). In aeronautical engineering, adjusting a detailed solid model in traditional CAD to evaluate alternative wing sweeps or fuselage dimensions can take days. OpenVSP accelerates preliminary design by defining vehicle geometry through high-level engineering parameters rather than low-level geometric primitives.

The codebase originates from 1990s NASA research, including the Rapid Aircraft Modeler (RAM) and Vehicle Sketch Pad (VSP) developed by J.R. Gloudemans and teams at NASA Ames and Langley Research Centers. NASA released the tool as open source on January 10, 2012, under the NASA Open Source Agreement (NOSA) Version 1.3 (NASA Catalog Reference LAR-17491-1). OpenVSP runs on Linux, macOS, and Windows, following open computational modeling principles outlined in Better Scientific Software guidelines.

Its scope covers conventional fixed-wing aircraft, uncrewed aerial vehicles (UAVs), electric vertical takeoff and landing (eVTOL) designs, and multi-stage launch vehicles. Rather than serving manufacturing fabrication, OpenVSP generates analysis-ready geometries, wetted areas, and surface meshes for rapid trade studies.

How it works or how it is used in practice

OpenVSP organizes vehicle geometry hierarchically. Engineers assemble configurations from standardized parametric components—such as wings, fuselages, nacelles, propellers, and control surfaces—governed by physical aerospace parameters:

• Wings: Controlled by span, planform area, aspect ratio, taper ratio, sweep angle, dihedral, twist, and cross-sectional airfoil profiles (such as 4-digit NACA profiles or coordinate files).
• Fuselages: Defined by longitudinal stations, length, diameter, and cross-sectional shape curves.
• Propulsion: Represented as multi-blade propellers, actuator disks, or flow-through nacelles to model distributed electric propulsion (DEP).

Once geometry is defined, OpenVSP executes integrated engineering analysis modules (McDonald and Gloudemans, AIAA 2022-0004):

• CompGeom: Intersects overlapping component meshes, trims interior geometry, computes wetted areas and enclosed volumes, and exports watertight triangulated surface meshes.
• VSPAERO: A built-in vortex-lattice method (VLM) and 3D panel solver that calculates lift distributions, induced drag, and stability derivatives, including unsteady prop-rotor wake interactions.
• Mass and Structural Slicing: Generates internal structural layouts (ribs, spars, skins) to compute preliminary center-of-gravity (CG) locations and export finite element analysis (FEA) decks.
• Automation: Features Python and AngelScript APIs for headless batch execution, parameter sweeps, and multidisciplinary design optimization (MDO) within research software engineer workflows.
• Export: Outputs STEP and IGES for CAD, STL and OBJ for 3D printing, and Cart3D (.tri) for Cartesian CFD grids.

Types or related concepts

OpenVSP fills a distinct niche between low-order aerodynamic screening codes and production manufacturing CAD systems. The table below outlines how these tools compare across geometry representations and analysis capabilities:

Tool or Paradigm	Geometry Representation	Primary Phase	Aerodynamic / Analysis Scope	Export Formats	Core Advantage
OpenVSP (NASA)	Parametric component surfaces and cross-sectional lofts	Conceptual and preliminary design	Integrated VLM and panel solver (VSPAERO), wetted area, mass/CG	STEP, IGES, STL, Cart3D, DXF, FEA decks	Geometry regeneration in seconds; automated surface intersection trimming
Solid CAD (e.g., CATIA, SolidWorks)	Boundary representation (B-rep) solids and NURBS	Detailed engineering and manufacturing	Requires external solvers or commercial simulation add-ons	STEP, IGES, Parasolid, native assembly files	Sub-millimeter fabrication tolerances and mechanical fastener placement
Quasi-1D / 2D Codes (e.g., AVL, XFOIL)	Vortex lines, lifting surfaces, and 2D foil panels	Initial aerodynamic screening	Linear lift, induced drag, stability derivatives	Aerodynamic coefficient polars and text tables	Instantaneous coefficient calculations without full 3D surfaces
Unstructured CFD Meshers (e.g., Pointwise)	Polyhedral or tetrahedral volume boundary-layer grids	Detailed aerothermal simulation	Prepares grids for Navier-Stokes (RANS/LES) flow solvers	OpenFOAM, CGNS, Fluent mesh formats	Resolving boundary layer separation, turbulence, and shock waves

Where it matters for labs, clinics or supply decisions

OpenVSP serves critical functions across academic, government, and industrial aeronautical laboratories:

• Wind Tunnel Model Prototyping: Research facilities use OpenVSP outer mold line (OML) models to direct laboratory 3D printers. Scaled aerodynamic wind tunnel models can be designed, trimmed, and printed in a single day for experimental testing.
• Multidisciplinary Design Optimization: In flight research labs, OpenVSP acts as the upstream parametric geometry engine in automated optimization pipelines. Managing numerical sweeps across configurations requires strict experimental controls, matching practices for reproducible numerical simulation seeds.
• Research Software Reproducibility: Because OpenVSP models are stored in lightweight, plain-text parameter files (.vsp3), researchers can publish full geometry specifications alongside papers. This practice aligns with Journal of Open Research Software publication standards, enabling peer reviewers to reproduce flight geometries exactly.
• Laboratory Budget Efficiency: Commercial aerospace CAD packages require expensive recurring seat licenses. Utilizing open-source tools for conceptual trade studies conserves laboratory funding while maintaining interoperability with industrial CAD via STEP and IGES exports.

Common misunderstandings

Engineers and researchers frequently encounter several misunderstandings when evaluating OpenVSP:

• OpenVSP does not replace production CAD: OpenVSP is intentionally designed for rapid trade studies rather than manufacturing drawings. It omits machining tolerances, sheet metal bends, and fastener patterns; production CAD takes over once vehicle architecture is frozen.
• VSPAERO is not a Navier-Stokes viscous solver: VSPAERO uses inviscid vortex-lattice and panel methods. While accurate for induced drag, lift-curve slopes, and trim, it cannot resolve deep stall, separated turbulent flows, or transonic shock waves without empirical corrections or higher-fidelity CFD coupling.
• Geometry models are parametric, not polygon meshes: Unlike standard 3D mesh modeling tools, adjusting an OpenVSP model requires altering underlying parametric inputs (such as wing sweep or thickness ratio), which regenerates mathematical surface lofts deterministically.

FAQ

What license governs OpenVSP, and is it free for commercial research?

OpenVSP is released under the NASA Open Source Agreement (NOSA) Version 1.3. It is free open-source software available for academic, governmental, and commercial use without licensing fees.

Can OpenVSP export geometry directly into CFD and FEA software?

Yes. The CompGeom module resolves intersecting component surfaces and exports watertight triangulations in formats such as Cart3D (.tri), STL, and OBJ. OpenVSP also generates internal structural layouts and exports structural element decks for finite element analysis.

How does OpenVSP support automated parameter sweeps in research?

OpenVSP includes native AngelScript and Python APIs (the openvsp module). Researchers can launch OpenVSP in a headless, non-graphical batch mode on compute clusters to iterate parameters, execute VSPAERO calculations, and export geometry automatically.

Where can researchers access official tutorials and community models?

NASA hosts the OpenVSP Ground School through NASA Langley Research Center, providing video tutorials on modeling techniques. The community-maintained OpenVSP Airshow offers a public repository of pre-built aircraft configurations and wind tunnel models.

Sources

• NASA Software Catalog, “Vehicle Sketch Pad (VSP) / OpenVSP,” NASA Reference Number LAR-17491-1, accessed November 9, 2026, https://software.nasa.gov/software/LAR-17491-1
• OpenVSP Official Project Portal, “About OpenVSP” and “NASA Open Source Agreement v1.3,” accessed November 9, 2026, https://openvsp.org/
• NASA Langley Research Center, “OpenVSP Ground School,” accessed November 9, 2026, https://www.nasa.gov/software/openvsp-ground-school/
• McDonald, Robert A., and James R. Gloudemans. “Open Vehicle Sketch Pad: An Open Source Parametric Geometry and Analysis Tool for Conceptual Aircraft Design,” AIAA SCITECH 2022 Forum, AIAA 2022-0004, January 2022, DOI: 10.2514/6.2022-0004.
• McDonald, Robert A. “Configuration Geometry Analyses in OpenVSP,” AIAA AVIATION 2026 Forum, AIAA 2026-4357, June 2026, DOI: 10.2514/6.2026-4357.
• Nascenzi, Thomas, Timothy Cuatt, and Robert A. McDonald. “Advanced Scripting Development and Application of OpenVSP,” AIAA SCITECH 2025 Forum, AIAA 2025-0372, January 2025, DOI: 10.2514/6.2025-0372.