QUAD

QUAD, NODE1, NINTR, NODE2, NFILL, NSTRT, NINC, PKFAC
Generates a quadratic line of nodes from three nodes.

Valid Products: Pro | Premium | Enterprise | PrepPost | Solver | AS add-on

NODE1

Begin fill-in from this node location. If NODE1 = P, graphical picking is enabled and all remaining command fields are ignored (valid only in the GUI).

NINTR

Intermediate or guiding node. Quadratic curve will pass through this location. NINTR may have any node number and any location. If the quadratic line also generates a node with number NINTR, the generated location overrides the previous NINTR location.

NODE2

End quadratic fill-in at this node location.

NFILL

Fill-in NFILL nodes between NODE1 and NODE2 (defaults to |NODE2-NODE1|-1). NFILL must be positive.

NSTRT

Node number assigned to first filled-in node (defaults to NODE1 + NINC).

NINC

Add this increment to each of the remaining filled-in node numbers (may be positive or negative). Defaults to (NODE2-NODE1)/(NFILL + 1), that is, linear interpolation.

PKFAC

Peak location factor. If PKFAC=0.5, the peak of the quadratic shape occurs at the NINTR location. If 0.0 < PKFAC < 0.5, the peak occurs to the NODE2 side of the NINTR location. If 0.5 < PKFAC < 1.0, the peak occurs to the NODE1 side of the NINTR location. Defaults to 0.5.

Notes

Generates a quadratic line of nodes (in the active coordinate system) from three nodes. The three nodes determine the plane of the curve and may have been defined in any coordinate system. Any number of nodes may be filled-in and any node number sequence may be assigned.

The quadratic line feature uses three nodes (NODE1,NINTR,NODE2) to determine the plane of the curve. The curve passes through the three points, beginning from NODE1, through the intermediate (or guiding) point NINTR, and toward NODE2.

Generated nodes are also quadratically spaced. If the guiding node number is within the set being generated, it will be relocated according to the quadratic spacing.

The peak location factor is used to determine how the quadratic fits through the three points. Various nodal progressions can be obtained by different combinations of PKFAC and the guiding node location. If the guiding node is at mid-length between NODE1 and NODE2, 0.293  PKFAC< 0.707 will ensure that all generated nodes fall within the NODE1,NODE2 bounds. In the limit, as PKFAC approaches 0.0, the peak approaches the line through NODE1 and NINTR at an infinite distance from NODE1. The QUAD command generates quadratic lines of nodes, which in turn may be used as a base line for generating irregular surfaces of nodes (by repeating (*REPEAT), generating (NGEN, NSCALE), etc.). Irregular surfaces may also be generated with the meshing commands.

Menu Paths

Main Menu>Preprocessor>Modeling>Create>Nodes>Quadratic Fill