TIED contacts help “bond” two surfaces of different mesh densities. When using the default constraint method, the projection distance of the slave node onto to the closest master segment must be zero and this is achieved by LS-DYNA by updating the slave node coordinates such that it lies on the master surface. This coordinate update is done during initialization and does alter the geometry. To avoid significant element distortion, LS-DYNA uses a built-in tolerance to discard slave nodes that are “too-far” from the master surface. In some cases, the internal tolerance could lead to slave nodes being discarded by LS-DYNA which may otherwise be required to be tied. To enable this, LS-DYNA allows a user-defined tolerance using SST as shown below.