The projection limit keeps the mesh from resolving small tolerance differences between the curves adjoining and geometry surfaces. Also allows the user to bypass projection where surfaces and outline curves do not fully match each other. If the Projection limit is set to a non-zero value, P, the nodes within distance P of the edge of a curve and within distance P of the edge of a face will not be projected. Instead, they will be linearly interpolated based on the underlying face/curve shape. Example: In the case of a strut in a diffuser, nodes within 1.3 units of the profile curves at the hub and shroud of the diffuser are positioned by an interpolation of the shape of the airfoil between the hub and shroud. This is like saying the last 1.3 units of the surface/curve geometry at either end of the airfoil is ignored and deduced by interpolation The same thing is true of curves. 1.3 units away from where 2 curves meet, the curve starts getting ignored by the mesher and nodes are positioned based on an interpolation of the curve shape > 1.3 units away from the end. This ensures a smooth transition where the actual curves may not be meeting fully The value of projection limit required to prevent folding mesh will vary depending on the units of the geometry and the quality of the underlying CAD. Parasolids usually import the best, whereas IGES can have large gaps and poor tolerances