Short Answer
vyzn does not evaluate your IFC by re-meshing the raw geometry itself. Instead, it uses the quantities and properties stored in the model – specifically areas and lengths from the IFC quantity data (Qto property sets such as Qto_WallBaseQuantities or Qto_SlabBaseQuantities) or from the VYZN property sets. Complex elements such as curtain walls or stairs are recognised and imported, and freeform geometries are displayed correctly in the 3D viewer. What matters for the calculation is that a reliable reference area (or length) is available for the element.
Why It Matters
This approach is a deliberate design decision: the quantities written by the authoring tool are more precise and more traceable for LCA, cost and energy calculations than a subsequent tessellation of the geometry. That is why vyzn relies on the quantity data from your model rather than recalculating it from the raw geometry.
How It Works in vyzn
Special element types at import
Curtain walls (IFCCURTAINWALL), stairs (IFCSTAIR/IFCSTAIRFLIGHT), ramps (IFCRAMP), railings (IFCRAILING), mullions/transoms (IFCMEMBER) and plates (IFCPLATE) are recognised and imported:
- Curtain walls are assigned to the "Wall" component group.
- Stairs, ramps and railings go into the collective group "Other".
They are therefore included in the model and in the quantities, but not as standalone special types with dedicated building physics.
Freeform and complex geometries
The 3D viewer (based on Autodesk Forge) displays freeform and complex geometries correctly. For the calculation, however, it is essential that a reliable reference area (or length) is available for the element.
The limits – and how vyzn deals with them
If a complex element does not come with clean quantities, vyzn cannot derive them from the freeform geometry. This is where Deep Model Processing with the vyzn Referenzmodell™ comes in: it automatically enriches and corrects missing or inconsistent areas (the "Auto Correct" option, suitable for most models). If a reference area is missing for a critical component (walls, slabs, roofs, windows, doors), vyzn flags this visibly during import and points out the impact on the results.
Frequently Asked Questions
What should you do if areas are missing after the import?
If Deep Model Processing was skipped during import, the best approach is to restart the integration without skipping it (or with "Auto Correct"). If it has already been executed and areas are still missing, our support team will assist you specifically.
Can you set the energy reference area (EBF) manually?
Yes. You can set the EBF for the energy analysis according to SIA 380/1 manually at any time, or have it approximated from the model.
What about very special freeform constructions?
For very special freeform constructions, the best approach is to look at your specific model together with us to determine the optimal way forward.