The coordinates of all slideline contact nodes that are determined to have penetrated prior to the commencement of the analysis are automatically changed according to a perpendicular projection onto the opposing surface so that these nodes lie identically on this opposing surface. This is typically caused on slideline surfaces that are curved, the nodes of which may penetrate into the opposing flat segment approximating the curve. Increased mesh density will reduce the degree of realignment. The following message will be generated if this facility is triggered:

In LUSAS selecting Model properties> Attributes… (invoking the LUSAS option number 186) provides a switch to suppress this facility as required and is a useful method for simulating interference fit problems. In this way the forces required for the interference fit will come directly from the initial penetrations found by the slideline algorithms. If an interference fit analysis is not being performed and this option is set, the forces resulting from any initial penetrations may cause convergence difficulties if the coordinate change is large.

Note that the resetting of coordinates is not available for tied slidelines. Suppressing this facility should preferably not be used while "de-bugging" a data file since the suppression of the warning messages could remove some important indicators to data file errors.

The diagram below shows a node (m) that is part of mesh b₁ in initial contact due to poor mesh discretisation which is subsequently set to position (c).