2023-11-06 Blender BIM


Dion and I joined the same panel (as part of CAU - Solare seminar). Afterwards we decided to connect for me to learn more about BlenderBIM, the integration pain points and to virtual meet’n’greet. Hans and Yorik joined as well as interested parties.


  • Dalai Felinto (Blender)
  • Hans Goudey (Blender)
  • Dion Moult (BlenderBIM)
  • Yorik Van Havre (FreeCAD)

On the Blender Integration

  • In the future BlenderBIM could be tailored for non-Blender users (e.g., via Blender Apps).
  • Workarounds used by Blender BIM:
    • Own tab system.
    • Almost no Blender native-data - most of the information is centralized in an in-memory IFC, while operations happen using IfcOpenShell.
  • Showstopper:
    • Bug with context override.
    • 100,000 objects lead to poor performance.
    • It is not so easy to make a Tool that waits for input.
      • The Measure Tool seems to work as one would expect to build tools like this, but maybe doing this via Python is not easy/possible.
      • It would be interesting to know what is the actual issue.

BlenderBIM Wishlist

  1. Native section cutting
    • Blender supports some of this with Alt+B, but it has a few limitations (only works from point of view of selection, it has no control gizmos, it doesn’t show the cut geometry nicely).
    • It would be nice to have gizmo control over it, with nice thick lines.
    • Current attempts to solve this includes shader tricks.
  2. Perspective camera zoom limitations
    • View models from a camera often cuts either a section or floor plan.
    • The camera itself has a hardcoded zoom limit which make clicking on smaller objects very difficult.
    • This is pretty common for larger projects.
  3. Hierarchical tree views with drag and drop or multiselect
    • Note from Dalai: TreeView is not exposed to Python yet, but in the future it may address this.
    • This is the editor we use for lightlinking, node group panels and the asset browser catalogs.
  4. Multiline text input and line-wrapped labels
    • Just like a HTML textarea, it would be super nice to have a multiline text input.
    • This might be a hard one to implement, but there are various longer text data fields that exist in BIM that would be awesome to display.
  • 100,000 objects lead to poor performance.

related: Improve viewing of large federated models inside Blender · Issue #4279 · IfcOpenShell/IfcOpenShell · GitHub


I hope to see such great speedups inside blender!