Duplicate Vertex separated while simulation with Obj file

Hello Team,

I am working with simulation project using the openGL with Cuda.
I am using the toolkit 7.5 with VS 2010 using the quadro P4000 GPU.

I am loading the nonoptimize obj file (2 piece with common edges) and its loading fine, while i am using the simulation part from the cuda code, the common vertex are going separate.

In the cuda code creating the block using the face data from the obj file.

Please guide me how the obj file will simulate as single piece.

I can share obj file and any other information related the code.