User-Defined Slip Surface Overview

A User-Defined Slip Surface is a spherical, ellipsoidal or general slip surface created with one of the Add User-Defined Surface options:

These options are only enabled if the Surface Generation Method in the Slip Surface Options dialog is set to User-Defined Surfaces.

Search Methods and User-Defined Surfaces

When you add a user-defined slip surface:

You can apply the Surface Altering Optimization option to User Defined slip surfaces. In this case, the User Defined Surface will be converted to a spline surface and used as the starting location for the Surface Altering Optimization to search for lower safety factor surfaces.
You can use the External Geometry Composite Surface option with User-Defined slip surfaces.
You CANNOT use the primary Search Methods (e.g. Grid Search, Cuckoo Search, Particle Swarm) in conjunction with User-Defined Slip Surfaces. The two options are exclusive. If you need to analyze user-defined slip surfaces and search for critical surfaces using the primary Search Methods, then you will have to carry out the analyses separately.