I am able to get a smooth surface using the direction at https://community.altair.com/community?id=community_question&sys_id=7c941d99dbfa3c10cfd5f6a4e2961923&view_source=searchResult. However, when you convert the lines to primitive, you are unable to make adjustments to the input values and the model adjusted to the new values. The values I would like to optimize are D, d1, Bez_Ang_pnt, Bez_Ang_side, Bez_Ang_Tang, Bez_Bot_pnt, Bez_Bot_side, Bez_Bot_Tang. The L_W_R__D_d1_6B_input_V2_Bad_Loft.cfx is my attempts to loft, which all failed. The L_W_R__D_d1_6B_input_V2_Fill_hole.cfx is the Fill hole file. I need to know how to make a smooth surface like the one I get when I do a "fill hole" and adjust the values to run OPTFEKO. Will I have to use another Altair product to make this work?