Solibri IFC Optimizer, lost geometry in ventilation

[Hovinbole]

Hi everyone!

I have just started using Solibri IFC Optimizer and after my first collision control post using the optimizer, I noticed that I had zero issues with ventilation. I then checked the model and it turns out that the optimizer had removed all geometry, nothing in 3D left whatsoever.

We have 3 buildings in our project with the same firm modeling ventilation on all three. I tested the other two buildings with the optimizer and got the same results, file size reduced and geometry lost.

Building 1, the first I ran the optimizer on, went from 550mb to 330 approx.
Building 2, from 345mb to 224mb
Building 3, 220mb to 153mb

Considering there was no geometry left, but the file sizes where still a few mb’s, I tried opening the files in Archicad.
The whole model showed, in Archicad…
I am kind of confused and hope someone has some sort of solution or fix for this. Reducing the file sizes would help a lot as we have 75+ different models in total and the collective model is insanely heavy to run.

The optimizer has this far, worked on all other models, including electrical and other piping disciplines

All pointers as to why I lose geometry in this discipline would be helpful!