QUAD, NODE1, NINTR, NODE2, NFILL, NSTRT, NINC, PKFAC
Generates a quadratic line of nodes from three nodes.
-
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.
NINTRmay have any node number and any location. If the quadratic line also generates a node with numberNINTR, the generated location overrides the previousNINTRlocation.-
NODE2 End quadratic fill-in at this node location.
-
NFILL Fill-in
NFILLnodes betweenNODE1andNODE2(defaults to |NODE2-NODE1|-1).NFILLmust 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), i.e., linear interpolation.-
PKFAC Peak location factor. If
PKFAC=0.5, the peak of the quadratic shape occurs at theNINTRlocation. If 0.0 <PKFAC< 0.5, the peak occurs to theNODE2side of theNINTRlocation. If 0.5 <PKFAC< 1.0, the peak occurs to theNODE1side of theNINTRlocation. 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.