Notes

The ENSYM command is similar to the ESYM command except that it enables explicitly assigned element numbers to the generated set (in terms of an increment IINC). Any existing elements already having these numbers are redefined.

The operation generates a new element by incrementing the nodes on the original element, and reversing and shifting the node connectivity pattern. For example, for a 4-node 2D element, the nodes in positions I, J, K and L of the original element are placed in positions J, I, L and K of the reflected element.

Similar permutations occur for all other element types. For line elements, the nodes in positions I and J of the original element are placed in positions J and I of the reflected element.

See the ESYM command for additional information about symmetry elements.

This command also provides a convenient way to reverse shell element normals. If the IINC and NINC argument fields are left blank, the effect of the reflection is to reverse the direction of the outward normal of the specified elements. You cannot use this command to change the normal direction of any element that has a body or surface load. It is best to apply all loading only after ensuring that the element normal directions are acceptable.

Real constants (such as nonuniform shell thickness and tapered beam constants) may be invalidated by an element reversal.

For more information about controlling element normals, see Revising Your Model.

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