I am new to surfacing and have made a hood for a car I am building. In the past I've made simpler hoods from single lofts, and made proper molds for CNC'ing foam, but am finding my newest hood difficult. I am looking to exract the piece of the large extrude below the hood. I perform inhouse ABS vacuum forming over the machined foam block, but am unable to isolate a block from the model. I have tried using the mold command split with no luck. Also thickening the surface seems beyond me. I have attached the file in hopes that someone with more experience can help me.