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PolyData Message

  • Protocol Version: 3.0
  • Release Date: January 20, 2017

Summary

POLYDATA is used to transfer 3D polygonal data. The message format is designed based on the POLY DATA format defined in VTK file format and equivalent to VTK's vtkPolyData class. The message also supports dataset attribute field in VTK, including scalars, calar_scalars, vectors, vectors, normals, texture coordinates, and tensor, but not lookup table.

Message Types

POLYDATA

Data Type Description
NPOINTS uint32 Number of points
NVERTICES uint32 Number of vertices
SIZE_VERTICES uint32 Total size of vertices data
NLINES uint32 Number of lines
SIZE_LINES uint32 Total size of line data
NPOLYGONS uint32 Number of polygons
SIZE_POLYGONS uint32 Total size of polygon data
NTRIANGLE_STRIPS uint32 Number of triangle strips
SIZE_TRIANGLE_STRIPS uint32 Total size of triangle strips data
NATTRIBUTES uint32 Number of dataset attributes
POINTS POINTS Coordinates of point 0 - (NPOINTS-1)
VERTICES STRUCT_ARRAY Array of vertices
LINES STRUCT_ARRAY Array of lines
POLYGONS STRUCT_ARRAY Array of polygons
TRIANGLE_STRIPS STRUCT_ARRAY Array of triangle strips
ATTRIBUTES ATTRIBUTES Attributes
  • POINTS
Data Type Description
P0X,P0Y,P0Z float32[3] Coordinates for point 0
... ... ...
P(NPOINTS-1)X,P(NPOINTS-1)Y,P(NPOINTS-1)Z float32[3] Coordinates for point (NPOINTS-1)
  • STRUCT_ARRAY

STRUCT_ARRAY contains an array of point indices that represent a geometric structure, including vertices, lines, polygons, and triangle strips. The number of structures (N_STRUCT) are specified by either NVERTICES, NLINES, NPOLYGONS, or NTRIANGLE_STRIPS (see the table above).

Data Type Description
STRUCT_0 POINT_INDICES Point indices for 0th structure
... ... ...
STRUCT_(N_STRUCT-1) POINT_INDICES Point indices for N_STRUCT-1 th structure
  • POINT_INDICES
Data Type Description
NINDICES uint32 Number of point indices
POINT_INDEX_0 uint32 Index for point #0
... ...
POINT_INDEX_(NINDICES-1) uint32 Index for point # (NINDICES - 1)
  • ATTRIBUTES
Data Type Description
ATTRIBUTE_HEADER ATTRIBUTE_HEADER Attribute header
ATTRIBUTE_NAMES ATTRIBUTE_NAMES List of attribute names
ATTRIBUTE_0 ATTRIBUTE_DATA Data for attribute #0
... ... ...
ATTRIBUTE_(NATTRIBUTE-1) ATTRIBUTE_DATA Data for attribute #(NATTRIBUTE-1)
  • ATTRIBUTE_HEADER
Data Type Description
TYPE_ATTRIBUTE_0 uint16 Type of dataset attribute #0 (including number of components for scalar type)
NATTRIBUTE_0 uint32 Number of data for attribute #0
... ... ...
... ... ...
TYPE_ATTRIBUTE(NATTRIBUTES-1) uint16 Type of dataset attribute #(NATTRIBUTES-1)
NATTRIBUTE(NATTRIBUTES-1) uint32 Number of data for attribute #(NATTRIBUTES-1)
  • ATTRIBUTE_NAMES
Data Type Description
NAME_ATTRIBUTE_0 char[] Name of attribute 0
(null) char (null)
... ... ...
... ... ...
NAME_ATTRIBUTE_(NATTRIBUTES-1) char[] Name of attribute (NATTRIBUTES-1)
(null) char (null)
Padding (int8) NULL Padding (inserted to make the size of ATTRIBUTE_NAMES even)
  • ATTRIBUTE_DATA
Data Type Description
DATA float32[NATTRIBUTE_0][NCOMP] Attribute data
... ...
DATA float32[NATTRIBUTE_(NATTRIBUTES-1)][NCOMP] Attribute data
  • Values for TYPE_ATTRIBUTE (16-bit)
    • 0-7 bit: Attribute Type:
      • 0x00: POINT_DATA / Scalars
      • 0x01: POINT_DATA / Vectors
      • 0x02: POINT_DATA / Normals
      • 0x03: POINT_DATA / Tensors
      • 0x04: POINT_DATA / RGBA
      • 0x10: CELL_DATA / Scalars
      • 0x11: CELL_DATA / Vectors
      • 0x12: CELL_DATA / Normals
      • 0x13: CELL_DATA / Tensors
      • 0x14: CELL_DATA / RGBA
    • 8-15 bit: Number of components -- must be 3 for Vectors and Normal, 9 for Tensor, 4 for RGBA.
  • Maximum length for attribute name is 255
  • If there are a pair of scalar and RGBA data with the same name and type (either POINT or CELL), those are used as scalar values and a look up table.
    • elements in RGBA data must be in the rage of [0.0, 1.0]

GET_POLYDATA

Data Type Description 
          |               |

STT_POLYDATA

Data Type Description 
          |               |

or

Data Type Description
RESOL uint64 Minimum interval between message (ns)*

See Time Stamp

STP_POLYDATA

Data Type Description 
          |               |

RTS_POLYDATA

Data Type Description
STATUS uint8 0: Success; 1: Error

Implementations