Bevel Plus issue when exporting models to Unity

[Anonymous]

Hi, I am new to Maya. And I learnt to use Bevel plus to make a solid surface from a closed CV curve. It worked fine in Maya, however, when I exported it to Unity, the surface disappeared. I attached the screenshots below. Does anyone know how to solve it ? Thank you.

[mspeer]

Hi!

Convert to Polygons before export.