When defining the parameters required for the various types of section, you will be asked to specify how the section profiles are to be calculated. This will appear as a Profile group on the appropriate Definition page and will contain two check boxes.
DTM Facets - This option allows you to specify the use of the DTM triangles in a model to calculate a section profile. Points will be calculated where each triangle intersects the section cut line. Also, the group information stored with each triangle is extracted in the form of a name and a depth. If an edge of a triangle is formed by a line feature segment, the code of the line feature is stored with the calculated point.
Features - This option allows you to specify the use of line features to calculate the section profile. This calculates points where the section cut line intersects with features. This option is only useful if the model has not been created or you wish to section through curved features.
In practice, there is no need to have both options checked. If you have both checked and there are curved features, it is possible that you will end up with two points on the profile that represent the same linear feature.