Describe all types of projects requirements according to Wijnen.

Preconditions:

It forms the context in which the project should be executed. Illustrations include legislation, working-circumstance regulations and approval needs. These needs cannot be affected from during the project.

Functional needs:

These are needs which have to do along with the quality of the project output (for example how energy-efficient should an automobile be or how many rooms should a modern building have?).

Operational needs:

It includes the use of the project outcome. For illustration, after a software project has been realised, then the number of malfunctions which arise should be decreased by ninety per cent.

Design restrictions:

Finally these are needs that involve the definite realisation of the project. For illustration, the project cannot comprise the use of toxic materials or international partners for whom this is unclear whether they use child labour.