Hi,
By working with a precast element, you have access to Precast Catalog which contains plenty of sub catalog.
They are catalog for concrete grade, steel grade, diameter, fixtures... and element plans.
Any fixture (library graphic) which are integrated to a precast must be attached to a Precast Fixture catalog entry.
When this operation is done, than you won't have any error message and your export will be done included all fixtures and also probably.
Since the version 2022, Allplan generate an IFC embebbed precast sub component.
If you are not able to fix your issue, you contact your technical support or the precast support (support.precast@allplan.com).
Bye
Mr Judy GURAVADU
Responsable Technique Préfabrication & Ingénierie
Precast Sales & Support
Allplan France & Allplan Precast
Since 2006