# SUBSYSTEM OVERVIEW

STEP To/From GDX Conversion (SGDX) Subsystem

The SGDX subsystem provides functions to convert applicable STEP geometry entities to GDX entities and GDX entities to STEP geometry entities. The function sgdx_GetGDXData will return the GDX entities corresponding to the given STEP entity, while the function sgdx_GetSTEPData will return the STEP entities corresponding to the given GDX entity. The SGDX_NOOPT option should be specified for any unused option masks.

See the manual pages for the full bindings.

# ENTITY ATTRIBUTES

The SGDX substem provides functions to transfer attributes between STEP Topological entities and GDX Geometric entities.

In AP214, Color Attribute is accessed through STYLED_ITEM or OVER_RIDING_STYLED_ITEM definition which is defined only at Edge_curve, Face and Solid levels. While creating GDX Attribute Entity for a geometric entity, SGDX subsytem finds parents for GDX Geometric entities at those levels and gets its color values from corresponding step entity. Same procedure is followed when updating the STEP entities with GDX attributes.

The following functions are used in the attribute translation.

sgdx_ModelEntitiesToGDXAttrs

Creates GDX Attribute Entities for all Geometric entities in the GDX Model

sgdx_EntityDEToGDXAttributes

Creates GDX Attribute Entity using GDX Geometric entity and its STEP entity

sgdx_GDXAttrsToModelEntities

Populate GDX attributes from GDX Model to related STEP Entities

sgdx_PopulateSTEPAttributes

Update STEP Entity with Attributes from GDX Attribute Entity

s214_EntityGetColor

Gets the Color definition for the given STEP entity

s214_EntityGetStyledItem

Gets a Styled Item for the given STEP entity

s214_StyledItemGetColor

Get Color Ptrs for the given STYLED_ITEM entity

Please refer "ENTITY ATTRIBUTES" section of gdx_intro man page.