The role of an interior architect is to make a room seem alive and they have to do that by bargaining for the needs of the client. Interior architecture is pretty intimate and it has to fit with the behavior and traditions of the client and can do this by using details: colors, furniture so that the room would not just fulfill its purpose and be comfortable but would fit with the other rooms of the house or apartment. That is what an interior architect is for.
The engineering process is pretty much the same as of a usual architect, the realization of the schematics goes after the same tempo.
An interior architect can be a free worker or work in a company, when in a company the architect is not aloud to make publicity for any special products of just one organization.
An interior architect can engineer rooms everywhere for example apartments, company buildings, hotels, museums, malls and so on.
The architect is responsible for the engineering; he/she should also assist making the contracts with the employees, be the responsible person for the implementation of the project and assist in payment of the employees when the project is finished.
The project is a written contract between the customers no matter if a private person or company who states that the customer agrees with planned actions and the interior architect is going to be responsible for the project till the final end.