Select the Solid Elements option under Type in the Physical Property form. You will notice that solid elements can only be selected in Assembly context.
Part Context
Assembly Context
- Material Axes: Assign a material coordinate system for elements with orthogonal material. Global and User-defined Coordinate can be assigned as the material coordinate.
Solid Parabolic Tetrahedral Element Connection
Solid Element Coordinate System
It is strongly recommended to use parabolic tetrahedral elements for accurate results. Use linear tetrahedral elements carefully. An example application of linear elements might be to reduce the size of the model in areas where results are not of primary interest or in heat transfer analysis, but not when thermal stress analysis will be carried out.