CORD3R

Bulk Data Entry

CORD3R – Rectangular Coordinate System Definition, Form 3

Description

The entry defines a rectangular coordinate system using three grid points. The first point is the origin, the second lies on the X-axis, and the third lies on the X-Y plane (see Figure 1).

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
CORD3R	CID	G1	G2	G3	CID	G1	G2	G3

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
CORD3R	3	16	32	19

Field

Contents

CID

Unique coordinate system identification number.

(Integer > 0)

G1, G2, G3

Grid point identification numbers of points used to uniquely define the rectangular coordinate system (see Figure 1).

(Integer > 0; G1 ≠ G2 ≠ G3)

cord3r

Figure 1: Defining a Rectangular Coordinate System (CID) using grid points G1, G2 and G3.

Comments

1.	Coordinate system identification numbers on all CORD1R, CORD1C, CORD1S, CORD2R, CORD2C, CORD2S, CORD3R, and CORD4R entries must all be unique.

2.	A duplicate identification number is allowed if the CID and GID are identical and the coordinates are within the value set by PARAM, DUPTOL. Refer to Guidelines for Bulk Data Entries.

3.	The three points G1, G2, and G3 must be non-collinear. Non-collinearity is checked by the geometry processor.

4.	The location of a grid point (P in Figure 1) in this rectangular coordinate system is given by (X, Y, and Z).

5.	The displacement coordinate directions at P are (Ux, Uv, and Uz) as shown in Figure 1.

6.	A maximum of two coordinate systems may be defined on a single entry.

7.	In geometric nonlinear analysis, CORD3R is a moving coordinate system. It moves with grid points defining the system.

The implementation of CORD3R in OptiStruct is different from that of NASTRAN. A CORD3R coordinate system in OptiStruct can be defined by specifying grid point identification numbers for the Origin, X-axis and the XY plane, whereas CORD3R in NASTRAN is specified with reference to the Origin, Z-axis and the XZ plane.

9.	This card is represented as a system in HyperMesh.