Main Help → All Commands → FEA Mesh / MPM Grid and Material Points → PolyPt
A series of PolyPt
commands defines a shape specified by some points to be filled with material points, to assign element materials, to be defined as a hole, or for boundary conditions. It can define either a 2D shape or a 3D shape.
In 2D simulations, the PolyPt
command points define a polygon region:
PolyPt (x1),(y1) PolyPt (x2),(y2) . . . PolyPt (xn),(yn) PolyPt
where x
and y
(or R
and Z
if axisymmetric) are 2D coordinates of points (in length units) to be connected into a polygon. If the arguments are omitted, the polygon is completed, which allows a region or hole to have more than one polygon. The last point will automatically be connected to the first point to define a closed polygon.
In 3D simulations, the PolyPt
commands define 4 to 8 points in 3D space defining various types of 3D shapes:
PolyPt (x1),(y1),(z1) PolyPt (x2),(y2),(z2) . . . PolyPt (xn),(yn),(zn) PolyPt (style),(details)
where (x
, y
, z
) are 3D coordinates of points (in length units). The polyhedron defined by the points is determined by the final PolyPt
command where:
(style)
is type of 3D shape with options:
style='pyramid'
: define a pyramid shape for which the first point is the apex of the pyramid and the remaining 3 or 4 points define a triangular or quadrilateral base. If the 4 base points are not coplanar, the base will have two face triangles connected by a line between the 1st and 3rd points.style='trivectors'
or style='tripts'
: define a triclinic shape from 4 points. The first point is one corner or origin of the shape. For trivectors
, the remaining points are vectors along the three edges emanating from the shape's origin. For tripts
, the remaining points are end points of those vectors.style='box'
: define an arbitrarily shaped 8-corner box from 8 specified points. Points 1,2,3,4 define bottom face of box and 5,6,7,8 define the top face (ccw around each face with point 5 above point 1). The points can be specified in any order as determined by the (details)
parameter.PolyPt
command to specify the (style)
of 3D shape or if the number of points does not correspond to those needed by the specified style. This command finishes the polyhedron definition, but a region or hole can have more than one polyhedron.(details)
defines order of the points when the shape style is box
as list of 8 integers each within the range of 1 to 8.Some graphics illustrating these shapes is on-line here.