3D Model file description

From model geometry collection site, you can download geometry files in a format ( .d ). The format contains geometry information, such as the number of vertices, the number of polygons, list of vertex coordinates, and the surface information.

e.g.)  lbox.d

data 12	8
-.5	0.0	-.5
0.0	0.0	-.5
0.0	.5	-.5
.5	.5	-.5
.5	-.5	-.5
-.5	-.5	-.5
-.5	0.0	.5
0.0	0.0	.5
0.0	.5	.5
.5	.5	.5
.5	-.5	.5
-.5	-.5	.5
4	3	9	10	4
4	1	7	8	2
4	12	6	5	11
4	7	1	6	12
4	9	3	2	8
4	10	11	5	4
6	9	8	7	12	11	10
6	4	5	6	1	2	3

From the beginning, the above file has

12: number of vertices            
8: number of polygons
12 lines of vertex coordinates (x, y, z order)
8 lines of polygon list (number of vertices in the polygon, vertex indices) 
For example, in the above geometry, the first polygon contains four vertices of index number 3, 9, 10, and 4.