Use this option to define a new compatibility type by clicking 
in the Compatible nodes dialog. After you select this option the following dialog displays. This dialog shows an example for a 2D structure.
The dialog consists of the following tabs:
- Compatibility
- Elastic
- Damping
- Gap
- Non-linear.
On the Compatibility tab, you can define the compatible degrees of freedom in a node. Similar symbols are assumed as in the case of supports: displacements UX, UY, and UZ; rotations RX, RY, and RZ.
On the Elastic tab, you can define an elastic type of compatibility, accompanied by adequate coefficients (parameters: KX, KY, KZ, HX, HY, and HZ have the same orientation as in the case of the definition of elastic supports). The coefficients HX, HY, and HZ are always expressed in length units or radians.
On the Damping tab, you can define a compatibility type recognizing the effect of damping. The coefficients: CX, CY, CZ, CRX, CRY, and CRZ (components of the damping matrix C) have the same orientation as in the case of the definition of elastic supports. The number of available damping coefficients depends on a selected structure type (2D frame, 3D truss, plate, and so on.) The defined damping value is considered only in time history analysis.
Additionally, the dialog has a Damping according to PS92 button. When pressed, it opens the dialog for defining the damping values used in the formula given in the seismic code PS 92. As indicated in point 5 of section 6.2.3.4 in the French seismic code PS 92 (NF P 06-013), it is necessary to consider the structure's interactions with the ground, and thus its influence on the value of the structural damping of a structure.
The definition of compatibility with gap consists in indicating the compatibility name, selecting the fixed or released degrees of freedom and indicating the values of the allowable displacement or rotation for the released directions. If the direction is fixed, the displacement is equal to zero.