I am trying to cut a rectangular hole in an arbitrary triangular region in space which has been meshed with plates. Is there a way to orient the construction grid (for the "snap node/plate" feature) to align with three pre-defined nodes (i.e. the corners of the triangle) to simplify removal of the rectangular feature inside? The angle of the triangle is very odd and I am concerned about the nodes defining the rectangle being slightly out of plane if I try to set the construction grid manually based on the coordinates and angle of the triangle.
Using STAAD's graphical tools, it is quite difficult to insert an opening after the plate has been meshed, unless your plate elements are aligned in a manner that exactly matches the boundary of the opening. The process is far less painful if the hole is specified before the meshing process commences. To do that, please have a look at the solution described later in this section under the topic "Generation of a plate element mesh for an irregular slab with holes/openings"
Alternatively, you may use Parametric Models option as described in section 188.8.131.52 titled Geometry | Create Parametric Models