I mainly deal with transistor models, HSPICE simulations and extraction. Hence, I am not very familiar with flows beyond extraction and someone else might be able to provide you with detailed information regarding SDF/SPEF. As far as I understand, SPF file is what you get after RC extraction. You can use it in tools like PrimeTime to get SDF, which has the cell delay information. This is calculated using the information in the SPF file (I think).As for the Resistance and Capacitance, are they always "parasitic"? I mean, there are SDF and SPEF. As for the RC-extraction for SDF, are the resistance and capacitance still parasitic?