Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Thermal analysis of IFC building models using voxelized geometries

Thermal analysis of IFC building models using voxelized geometries

Multi-disciplinary three-dimensional representations of building designs are available in BIM. However, thermal analysis often remains a manual task due to disparities in modelling: In IFC, buildings are decomposed into sets of elements with individual solid volumes. Thermal analysis requires interfaces between pairs of adjacent spaces.
In this work, we present an end-to-end solution for thermal analysis on IFC building models. We derive thin-walled thermal interfaces from architectural building models using voxelization. Neighboring spaces (separated by wall volumes in IFC) are touching after aligning to the voxel grid. The resulting mesh is converted into OSM files for OpenStudio/EnergyPlus.
This paper provides an implementation, discussion and initial validation. The algorithm depends on a minimal amount of information and favors robustness over accuracy, algorithms on voxels are robust. It is suitable for early design feedback and partial or imperfect scan2bim models.

Thomas Krijnen

October 04, 2021
Tweet

More Decks by Thomas Krijnen

Other Decks in Technology

Transcript

  1. Thermal analysis of IFC building
    models using voxelized geometries
    Thomas Krijnen and
    Tamer El-Diraby - Theohar Konomi - Ahmed Attalla

    View Slide

  2. Presenter
    • Thomas Krijnen
    • Post-doctoral researcher @ TU Delft, NL
    • Founder AECgeeks
    • Maintainer IfcOpenShell.org
    • ✉ [email protected]
    • 🐤 @aothms
    • 🖵 speakerdeck.com/aothms

    View Slide

  3. Rationale. Current IFC export architecture
    slow release cycles
    diffuse focus
    repeated effort
    no alternatives

    View Slide

  4. Rationale. Envisioned IFC export architecture
    fast release cycles
    focus
    reduced effort
    choice

    View Slide


  5. Unix philosophy
    Write programs that do one thing and do it well.
    Write programs to work together.
    Write programs to handle text streams, because that is a universal interface.

    Douglas McIlroy, Peter H. Salus

    View Slide

  6. Buildings as decompositions of
    solid volume
    products

    View Slide

  7. Thin-walled thermal interfaces
    http://nrel.github.io

    View Slide

  8. Geometry
    https://doc.cgal.org
    u (periodic) ⟶
    v ⟶
    0 2π
    0 1 2 3 4

    View Slide

  9. Process outline
    BIM input Grid overlay

    View Slide

  10. Process outline
    Space voxelization Discontinuities mesh

    View Slide

  11. Process outline
    Simplified mesh
    Associated semantics and projected
    sub-surfaces (windows, walls)

    View Slide

  12. Original IFC wall and infill elements

    View Slide

  13. Original IFC space geometries

    View Slide

  14. Voxelized space volumes (now
    touching)

    View Slide

  15. Exported model in Open Studio

    View Slide

  16. Statistics
    Voxel space volume 58071.25 (464570 × 0.53)
    IfcSpace volume sum 47257.91
    One-sided thermal interface sum 36640.25
    IfcWall area sum (length x height) 16683.05
    IfcSlab area sum (volume / thickness) 20315.27
    IfcWall + IfcSlab area sum 36998.32
    Number of IfcSpaces 218
    Number of unique boundary sides 208

    View Slide

  17. Synthetic model

    View Slide

  18. Effect of surface increase due to
    staircases

    View Slide

  19. Future work: automated detection of
    spaces
    (a) voxelized IFC geometries (b) exterior (c) interior as negation of b (d) spaces obtained as c - a
    a) b)
    c) d)

    View Slide

  20. Side step: other voxel use cases
    x
    y
    Door direction check
    Distance from exterior door
    Headroom check
    Safety barriers check

    View Slide

  21. Conclusion
    IFC as a driver for innovation in modular tools
    A robust, but less accurate, approach for thermal analysis on
    building models is presented
    Voxelization as a “low tech” solution to computational
    geometry problems in our industry

    View Slide