https://communities.bentley.com/products/geotech-analysis/f/forum/246564/plaxis-3d---surface-prescribed-displacementHello I&#39;m looking for a way to assign displacement fixities perpendicular to a plane which is not perpendicular to the principal axis x, y , z. For example asign radial displacement fixities to a curved surface (tunnel, shaft..) Thank you Malcolmen-USTelligent Community 12https://communities.bentley.com/thread/769939?ContentTypeID=1Fri, 16 Jun 2023 11:38:34 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:14b04f19-9282-4290-a5bf-6f6ad9d67b67Vasileios Basas<p>Hi Malcolm,</p> <p>Assigning a prescribed displacement fixity in a specific direction (i.e., radial) is unfortunately not possible. Unless you are also willing to fix the tangential direction, using the surface prescribed displacement may not work as expected.</p> <p>A suggestion that comes to mind is to define a set of fixed-end anchors with a high axial stiffness on that same plane. This element allows you to &quot;fix&quot; a point against a specific direction that you define yourself.</p> <p>Regardless, I think you should submit this idea to our portal: <a href="https://communities.bentley.com/products/geotech-analysis/i/ideas">communities.bentley.com/.../ideas</a></p><div style="clear:both;"></div>