Hello, I know it's been a wile since this post were made. I appriciate your answerr Array. I'm using Ansys workbench and I still don't know how to apply commands for pipe elements. I have a pipeline model shown in the figure below.nSECDATA command which looks like this:nSECDATA Do , Tw , Nc , Ss , Nt , Mint , Mins , Tinsnn And that's fine, I can live with that. But what I do not understand is how to define internal fluid density. Mint value refers to that:nMint = Material number of fluid inside of the pipe. The default value is 0 (no fluid). This value is used to input the density of the internal fluid. The fluid inside the pipe element is ignored unless the free surface in a global X-Y plane is added as face 3 (SFE) and is high enough to include at least one end node of the element.nVAL1) is the global Z coordinate of the free surface of the internal fluid of the pipe. The free surface coordinate is used for the internal mass and pressure effects. If VAL1 on the SFE command is zero, no fluid inside of the pipe is considered. If the internal fluid free surface should be at Z = 0, use a very small number instead. The pressure calculation presumes that the fluid density above an element to the free surface is constant.nnI think I understand what is free surface. In my case fluid is water and the entire volume of the pipe is filled with water. But what I don't understand is how to use the global value Z to define free surface. I started command line with SECDATA command. I would be so grateful if someone can help me to continue command line for first line body in order to define free surface and include weight of fluid.n