i get a unstructure grid used by cobalt format, and i have to read it. but cobalt's format is...???

The first line of the Cobalt grid file contains three integers :

nDimensions nZones nBoundaryPatches

where the meaning is self-explanatory.

The next line contains five integers :

nVertices nFaces nCells nVerticesPerFaceMax nFacesPerCellMax

where the last two quantities represent the maximum number of vertices defining a face and the maximum number of faces defining a cell.

For example, if the grid consisted purely of tetrahedra, nVerticesPerFaceMax and nFacesPerCellMax would be equal to 3 and 4, respectively.

On the other hand, if the grid consisted of tetrahedra, prisms, and pyramids, nVerticesPerFaceMax and nFacesPerCellMax would be equal to 4 and 5, respectively.

The next nVertices lines contain the x-, y-, and z-coordinates for each vertex.

The next nFaces lines contain the face-connectivity information, nVerticesPerFace <nVerticesPerFace> vertices Cell1 Cell2 where Cell1 and Cell2 are the two cells which share a given face. If a face lies on a boundary patch, the respective cell is given by the negative patch index.