I have designed a geometry for a 2D channel in autocad. Then I imported this design to solid word to do flow simulation. I extruded the 2D model to creat a 3D geometry for my simulation. Now, the problem is that solid work does not let me to do simulation becuase it thinks my model is not a channle. it considers my design as a rod not a channel or duct. solid work thinks that iside of my model is not empty. Is there any way that i can extrude my 2D design to 3D in away that it becomes a channel?
i have also attached 2D and 3D models.