I am creating parts to send to a CNC Mill. I originally made surface models so I would be able to run CFD analysis. After I verified my models fit the scope of the project I enclosed the model and successfully created a solid model using the knit feature. However, when I export this file to an IGES or STEP file and upload the content, the part become a surface again. I was curious as to what feature I need to change or if there was a process I missed in knitting my surface model into a solid model. Thank you for all your help.