A very basic question but an explanation would be highly appreciated.

Abaqus help manual classifies S4R shell element as a 3D shell element. The element shape however is 2D. Moreover, visualization module drop down box when selecting elements gives options such as 0D, 1D, 2D and 3D elements and when option 2D is exercised it allows selection of S4R elements in the model.

So my question basically is:

a) Is there a mismatch between abaqus help documentation and the actual program / software in this specific context ?

b) or is it that S4R is truly a 3D shell element as even though element shape is 2D it models 3D behaviour by 6 d-o-f nodal displacements at each of its 4 nodes ?