The engine extracts the corresponding 2D AutoCAD block, scales it according to the pipeline size, and places it on the isometric sheet with the correct orientation. Common Default SKEYs Reference List VAFB : Ball Valve, Flanged VAGL : Globe Valve, Flanged VAGA : Gate Valve, Flanged VACK : Check Valve, Flanged VABW : Gate Valve, Butt Welded ELBW : 90-Degree Elbow, Butt Welded ELSW : 90-Degree Elbow, Socket Welded TEBW : Straight Tee, Butt Welded REBW : Concentric Reducer, Butt Welded Flanges and Fasteners FLWN : Welding Neck Flange FLSO : Slip-On Flange GASK : Gasket STUD : Bolt/Stud Set How to Customize and Assign SKEYs
Place the valve in a 3D model. Generate an ISO. Your custom symbol appears.
3D Part Property (SKEY) -> ISO Symbol Map -> 2D Block in IsoSymbols.dwg autocad plant 3d iso symbol skey
You can set a default fallback SKEY in the IsoConfig.xml . If the part has an SKEY that doesn't exist, it will use, for example, UNKNOWN_VALVE .
The 2D block inside IsoSymbolStyles.dwg was drawn along the wrong axis, or connection points ( CP1 / CP2 ) are misaligned. The engine extracts the corresponding 2D AutoCAD block,
For example, a ball valve and a globe valve both use TYPE = VALVE . However, a flanged ball valve might use SKEY = VABF , while a socket-weld globe valve uses SKEY = VGSW . 2. Standard SKEY Naming Conventions
If your components are missing on an ISO, always check the Content ISO Symbol Definition in your Spec Editor . A single empty field there can break an entire drawing set. Your custom symbol appears
Common SKEY patterns and conventions Organizations often adopt naming conventions for SKEY codes so automation and human readers can infer component type and variant. Examples of typical conventions (organizations vary widely):
The software doesn’t magically know to use GAG . You must create a link.
In AutoCAD Plant 3D, SKEYs (Symbol Keys) are four-character codes used to map 3D piping components to their 2D isometric symbols. Without a valid SKEY, the software cannot determine which block to draw, often leading to disconnected or split isometric drawings. Understanding the SKEY Structure An SKEY typically consists of two parts: First Two Characters : Define the component type (e.g., for Flange, for Elbow, for Ball Valve). Last Two Characters : Define the end type or specific sub-type (e.g., for a Screwed Flange, for a Buttweld Elbow). The Mapping Workflow