Bulk Data 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 in the X-Y plane.


(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 SI Unit Example
CID Unique coordinate system identification.
Specifies an identification number for this coordinate system.
Specifies a user-defined string label for this coordinate system. 9

(Integer > 0 or <String>)

G1, G2, G3 Grid point identification numbers of points used to uniquely define the coordinate system. See Figure 1.

(Integer > 0; G1G2G3)


Figure 1. Defining a Rectangular Coordinate System (CID) using Grid Points G1, G2 and G3


  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. See Bulk Data Guidelines for further information.
  3. The three points G1, G2, G3 must be non-collinear. Non-collinearity is checked by the geometry processor.
  4. The location of a grid point (P) in this rectangular coordinate system is given by (X, Y, and Z). See Figure 1.
  5. The displacement coordinate directions at P are (Ux, Uy, and Uz). See 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.
  8. 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. String based labels allow for easier visual identification of coordinate systems, including when being referenced by other cards. Currently, coordinate systems with string IDs can be referenced only by JOINTG elements. For more details, refer to String Label Based Input File in the Bulk Data Input File.
  10. This card is represented as a system in HyperMesh.