Answer:
In the case of imported structures or surfaces inclined in space, it often happens that the nodes are affected by inaccuracies. By default, RFEM allows an inaccuracy of 0.5 mm. If this inaccuracy is exceeded, the following elements are no longer added automatically: nodes, lines, and openings.The same inaccuracy is tolerated even for curved surfaces (quadrangle).
However, if you still try to integrate the elements into the surface manually (Edit Surface → "Integrated" tab), the corresponding Warning 929 appears regarding the elements lying outside the surface.
By increasing the tolerance range via "Tools → Regenerate Model", the detection of the integrated elements is enforced, but usually results in a distorted FE mesh and thus also points of discontinuity in the FEM calculation.
For planar surfaces, you can settle the problem using the function "Edit → Project". To do this, you have to select the corresponding elements first. They are then projected onto the desired plane and can be recognized automatically.
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