Breps and simple Extrusions

Hi,

I am working with a geometry pipeline in GH and I was wondering why Rhino differs between BREPs and "Extrusions".

If you filter the geometrypipe to get all BREPs you also need to use the type "Extrusions" if you have simple boxes or tubes.

Those Extrusions were handled as "Rhino.DocObjects.ExtrusionObject" and they produce errors using them with additional components. Even the geometry-container shows up an error.

three questions:

1 - WHY?

2 - Is there a work-around for using boxes (created in Rhino) through a geometry pipeline as BREPS?

3- How can I speed up the pipeline? it´s so slooooow....

Best,

Thomas