element size =

A default edge length for elements, in the same units that the loaded model was created in (mm, inches, and so on).  This determines the default values whenever meshing, such as in the Automesh panel.

element order:

Toggle between using first-order (corner nodes only) and second-order (corner and mid-edge nodes) elements when meshing.

node tol

Node tolerance is essentially the resolution to which the finite element data in the model is maintained.  When you specify a node tolerance, any two nodes are considered to be coincident if the distance between them is less than the value.

feature angle

The feature angle tolerance specifies the maximum distance that the selected entity must be within to be included in the selection.  When you select entities by face, attached adjacent surfaces or elements are progressively selected as long as the angle between them is less than or equal to the feature angle.  This value is used in element cleanup.

topology revision:

This determines what to do when you change the model geometry's topology: keep its existing mesh, delete its existing mesh, automatically re-mesh it using the default values, or perform an "advanced remesh" which maintains node associations with surfaces (normal remesh may not always retain node/surface associativity, which may result in orphaned elements.)

pick tol

The pick tolerance specifies the maximum distance, in pixels, that the cursor can be from a graphical entity in order to select it.  When the pick tolerance is increased, it is easier to pick an entity.

zoom factor

The zoom factor specifies the multiplication factor that is used to increase or decrease the scale of the current view when you press the + and – keys or the zoom in/out button in the toolbar.

exponential

The exponential option specifies whether to display numeric fields in the user interface using an exponential format or a fixed decimal format.

Allow duplicate IDs

Available only in the Nastran and Altair OptiStruct user profiles, this option permits properties in different groups to have the same ID.