Here is a list of all namespaces with brief descriptions:

[detail level 12]

NACIS
NBrepRenderModes
NCFxNAWebSocketProtocol
NCloudGfxRecord
Ndst
NFacetModeler
NFacetModelerProfile2DBool	DOM
▼NFxBIM
NUnits
NFxHLR
NGeMesh
NGiMesh
▼NLODAlgorithm
NClustering
▼NOD
NFile
NOda
NOdaApp
NOdAve
NOdCharConverter
▼NOdDAI
NConsts
NUtils
NWrUtils
NOdDb
NOdDbAcisIO
NOdDbGripOperations
NOdDbGsManager
NOdDbHistoryInternal
NOdDbIndexFilterManager
NOdDbSymUtil
NOdDmUtil
NOdEd
NOdGeEllipArc
NOdGeTess2
NOdGiTools
NOdGiVisualStyleOperations
NOdGiVisualStyleProperties
NODGT_NAMESPACE
▼NOdIfc
NUtils
NOdIfc2x3
NOdIfc4
NOdIfc4x2
NOdIfcGsManager
NOdIfcInteroperable
▼NOdPdfPublish
NAction
NActivation
NArtwork
NBorder
NCamera
NDeactivation
NGeometry
NHighlighting
NImage
NLabel
NLighting
NPage
NPRC
NRendering
NText
NOdPs
NOdRx
NOdSi
NOdTf
NOdTfRevisionControl
NPDF3D_ENUMS
▼Nslimsig
Ndetail
NTmpFileHelper
NWt