Is it an ethically acceptable norm to take inspiration from an old/ ongoing architectural project being undertaken by some famous architect/planner ?

In case of Planner that is deferent because a lot of ower/consultant Impose on us some concpets. And also according to project importance to us.

"inspiration" that's means the architect will drive out a concept from another project, if the architect knows what he/she is doing, then the result will not look like the original project. in this case it is accepted, on the other hand, if it's just coping the project then it's not accepted