...
The Nodal Scene Interface (NSI) was developed to replace existing APIs in our renderer which are showing their age. Designed in the 80s, and extended several times since, they include features which are no longer relevant and design decisions which do not reflect modern needs. This makes some features more complex to use implement than they should be and prevents or greatly increases the complexity of implementing other featuresor prevents implementing others. The design of the NSI was is shaped by multiple the following goals:
Simplicity
The interface itself should be simple to understand and use , even – even if complex things can be done with it. This simplicity is carried into everything which derives from the interface.
...
Scene edit operations should not be a special case and be extremely efficient. There should be no difference between scene description and scenescene edits. In other words, a scene description is a series of edits and vice versa.
...
The interface should be accessible from a platform scripting language – one that is platform independent, efficient and easily accessible scripting language. Scripts can be used to add render time intelligence to a given scene description.
Performance and multi-threading
...