Hello,
You have to check :
- all your classification
- all your properties
There is no :
- 2D informations into a IFC
- quotations into a IFC
- annotations informations into a IFC
- shadow into a IFC
- link between 2d and 3D
And finaly you have to use the right translator option to export your IFC file
It is a great way to collaborate but there are a lot of details to check to use IFC files