If the pipe is longer and at the same slope, it does not make the slope inaccurate or invalid. If you use the difference in inverts at the side of the manhole and then use the lengths of pipe to center of the manhole then you would get a slightly inaccurate slope. C3D is using the length to center and the invert at center so the slope is accurate. Also the pipe run is continuous. Therefore, one does not need to account for gaps. If you need a accurate total pipe length, subtract x lf per structure. Have a number for thru manholes as well as manhole with only 1 invert.
People have come up with equations so that the pipe styles report the lengths they want to see for their design. Also they have used equations to report the inverts they need to see. A Search of this DG used to reveal these threads, I'm not sure if the search engine would find them today.
Dan
Dan
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