I'm not quite understanding what you are referring to. If you are meaning you want to show the pipe that is hidden then you will need to adjust your representation rules to have the back pen turned on. If this isn't what you are referring to then can you show a screen shot or elaborate a little on what you are needing.
wat i was asking is if one pipe is at some elevation and the second pipe is at exactly below the first pipe, so while extracting piping GAD from draft module i m not able to see that pipe which is at the lower elevation...
so how can solve this problem in draft...is there any thing u can tell me on this...it will be helpful...
That is the case I mentioned before. You will just need to make sure the backfacing pen is turned on and it will show the hidden pipe with whatever pen you specify. That is a change you will need to make at your representation rule used for that view.