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Open-source computational engineering

From BIM geometry to auditable engineering workflows

SAM is an open-source computational-engineering platform built around a shared analytical building model. It connects BIM, building physics, HVAC systems and simulation through reusable, traceable workflows.

Explore the platform SAM on GitHub Get SAM
SAM analytical model plan view with ventilation requirement and design airflow values for dwelling spaces.
E01 The SAM analytical model in the SAM Analytical desktop app: engineering data reviewed directly on the model, here ventilation requirements beside design airflows. F Part F requirement D design airflow Full size
Platform

One analytical model at the centre

Design tools feed a shared analytical building model. Engineering logic, systems and simulation all work on that model, and their results return to it.

Hosts & exchange

RevitRhinoGrasshopperIFCgbXMLLadybug ToolsBHoM

Shared core

SAM analytical modelSpaces, panels, apertures, adjacency, constructions, profiles, internal conditions, systems and results — one open JSON model, reused rather than rebuilt.

Engineering & systems

Geometry processingLoadsVentilationOverheatingHVAC systemsPsychrometrics

Simulation adapters

TasOpenStudio In development

Results, review & data

Results on the modelPlan overlaysAssessmentsReportsExcel & SQLite

Grasshopper is one host for SAM, not SAM itself. Tas is one simulation integration, not SAM itself.

What makes it different

  • One model, many workflowsGeometry, constructions, systems and results live in one analytical model that every workflow reads and extends.
  • Explicit engineering dataSpaces, adjacency, systems and their relationships are named, inspectable objects — not hidden tool state.
  • Deterministic and auditableWorkflows are repeatable and record what they used, so results can be reviewed and reproduced.
  • BIM and simulation connectedAuthoring tools and simulation engines are adapters around the model, not separate islands of data.
  • Decisions keep their authorityRegulatory requirements, engineering design and equipment capability stay distinct. See the principle
  • Open, scriptable, extensibleLGPL-licensed .NET code, scriptable from Grasshopper and C#, extended through independent modules.
Capabilities

What SAM does

Six capability families, each built on the same analytical model and implemented in public repositories.

Analytical modelling

Spaces, panels, apertures, adjacency, materials, constructions, profiles, internal conditions, systems and results in one model — inspected and edited in the SAM desktop apps.

Building performance

Loads, ventilation, overheating and thermal-simulation workflows on the model, including Part F ventilation traced to Approved Document F and Part O overheating assessed with CIBSE TM59.

HVAC & systems

Building systems as explicit engineering networks: plant rooms, air handling and ventilation, catalogue equipment selection, and psychrometric air processes on the Mollier chart.

Simulation interoperability

Tas integration for zone and systems simulation, with results read back onto the analytical model. Native OpenStudio conversion is in development.

Automation & computational engineering

Repeatable, scriptable workflows: a large Grasshopper component library, .NET APIs, scenarios run in series or in parallel, and data exchange for large models.

More modules, including the installer and release pipeline, are in the SAM-BIM organisation.

Flagship workflow

One example of SAM in practice: Part F to Part O

A three-dwelling model taken from ventilation requirement to overheating result. The analytical model, engineering logic, equipment data and simulation work together; each image is a real SAM screen.

  1. Analytical model
  2. Regulatory requirement
  3. Engineering design
  4. Equipment decision
  5. Simulation
  6. Engineering result
  1. 01 Regulatory requirement

    Part F calculates what must be achieved.

    SAM derives the Approved Document F airflow for each room from the model and shows it on the plan beside the design.

    Authority: Regulation
    One dwelling in the SAM plan view: Part F required airflow tags beside higher design airflow tags for bedroom supply, kitchen extract and transfer.
    E01Bedroom supply: Part F requires 63 l/s; the design holds 143 l/s. Two quantities on one plan.
  2. 02 Engineering design

    The engineer sets the design intent.

    Calculation proposes; the engineer reviews. Here design airflow is raised above the requirement to address overheating, while the requirement and the unit’s capacity stay unchanged.

    Authority: Engineer
    SAM Part O review showing separate required airflow, design airflow and selected ventilation-unit capacity.
    E02The regulatory requirement, engineering design and selected equipment capacity remain separate decisions.
  3. 03 Equipment decision

    SAM selects equipment and prepares the scenario.

    Each dwelling gets the smallest catalogue unit that meets its design duty; the unit’s maximum is a ceiling, never a design value. SAM then builds a repeatable simulation scenario and records its state.

    Authority: Product
    SAM Part O Prepare and Run interface showing a prepared ventilation scenario and simulation status.
    E03SAM materialises the engineering design into a deterministic simulation scenario and records the run state. Full size
  4. 04 Simulation & result

    Tas simulates; SAM assesses the result.

    The building is simulated in Tas and each room assessed against CIBSE TM59. On 2050s design weather this case still fails in 6 of 8 rooms — and SAM says so.

    Authority: Simulation
    SAM TM59 result review showing room-level overheating assessment outcomes from a Tas simulation.
    E04Example TM59 assessment showing the recorded room-level outcome; SAM reports the result rather than forcing a pass. Full size

On the 2026-Q3 release line, the same design can be simulated through inter-zone airflows or through explicit ventilation systems in Tas, including selected-product cooling, with the unchanged TM59 assessment. Technical record

SAM supports engineering workflows that contribute to assessment methods; compliance depends on the complete project methodology. A TM59 pass is an overheating result, not a Part O compliance certificate.

Engineering principle

Different engineering concepts stay different objects

A requirement is not a design, and a design is not what equipment can deliver. SAM keeps each quantity as its own object with its own authority, so one value never silently becomes another. The flagship workflow shows it with airflow:

01

Required

The minimum the regulation demands.

Authority: Regulation
02

Design

What the engineer decides to ventilate at.

Authority: Engineer
03

Selected capacity

What the selected unit can deliver — a ceiling, not a target.

Authority: Product
04

Operating

What flows in the simulated or commissioned system.

Authority: Operation
Evidence

Evidence, not claims

Each statement links to the public record behind it.

Automated testing

The core SAM model regression suite runs in continuous integration on every pull request and push.

CI test runs

Release acceptance

The published installer is built and payload-checked in CI and was smoke-tested manually in Rhino, Grasshopper, the Revit add-in and Rhino.Inside.Revit. The wider clean-install, upgrade and uninstall acceptance matrix was not re-run for this build.

Release acceptance notes

Simulation cross-checks

SAM’s TM59 figures checked against Tas’s own overheating report, with limitations stated.

Validation record

Regulatory traceability

Approved Document F traced paragraph by paragraph — an assessment, not a certification.

Traceability matrix

Peer-reviewed research

Published at building-simulation venues since 2021, including Springer and BSA proceedings.

Publications

Installable releases

Versioned Windows installer with release notes for Rhino, Revit and the SAM desktop apps.

Latest release
Research

Research & publications

Developed in the open; published at peer-reviewed building-simulation venues — from BIM-to-BEM model generation to psychrometrics and automated HVAC simulation.

Full list: ResearchGate – Michal Dengusiak.

People

Who builds SAM

An independent open-source project.

  • Michal Dengusiak Co-creator and engineering lead. Chartered Engineer; previously at Arup, Buro Happold and Hoare Lea. SAM-BIM is independent and not sponsored or endorsed by those organisations. LinkedIn · ResearchGate
  • Jakub Ziolkowski Co-creator; core platform development. LinkedIn · ResearchGate
  • Michalina Dengusiak Co-author of the SAM 2.0 and SAM 3.0 papers. LinkedIn · ResearchGate
Get SAMWindows installer for Rhino 8/9, Revit and the SAM desktop apps. Tas workflows need a Tas licence. Read the docsConcepts, modules and build guidance. DiscussionsQuestions and discussion on GitHub.