AutoCAD Plant 3D SKEY (Symbol Key) is a four-character code that determines the graphical representation of a 3D piping component in an isometric drawing. Without a valid SKEY, isometric generation may fail or split. Core SKEY Components An SKEY typically consists of two parts: First two characters : Define the component type for Elbow, for Valve). Last two characters : Define the or specific variant (e.g., for Buttweld, for Flanged). Essential SKEY Mapping Files
Understanding SKEYs requires working with two primary project files: IsoSkeyAcadBlockMap.xml : Located in the project's
folder, this file maps the SKEY to a specific AutoCAD block name. IsoSymbolStyles.dwg
: The block library that contains the actual geometry for the isometric symbols. Common Default SKEYs Component Type SKEY Examples Block Name (Default) Operator_Hand1 Operator_Lever How to Create a Custom Iso Symbol How to configure new isometric symbol in AutoCAD Plant 3D autocad plant 3d iso symbol skey
Modern versions of Plant 3D support Long SKEYs (more than 3 characters). This allows for intelligent matching.
For example, instead of one GAV symbol for all gate valves, you can have:
GATE-150LB → Block G15GATE-300LB → Block G30To do this, you do not change the SKEY property in the spec. Instead, use the SkeyMap XML to map the FullDescription or LongSkey: AutoCAD Plant 3D SKEY (Symbol Key) is a
<SkeyMap skey="GATE-150LB-FLANGE" acadBlock="G15" />
<SkeyMap skey="GATE-300LB-FLANGE" acadBlock="G30" />
Then, in your IsoSymbols.dwg, create blocks named G15 and G30 with different sizes (thicker flanges, different bolt patterns).
Before we modify anything, we must understand the hierarchy of how AutoCAD Plant 3D draws an isometric.
When you place a component in the 3D model (e.g., a gate valve), the part has several properties: Advanced Techniques: Using Wildcards and Long SKEYs Modern
When you run the IsoConfig and generate the drawing, the Plant 3D ISO engine reads the SKEY from the model. It then looks at the IsoSymbols.dwg file (or your project’s symbol map) and finds the block named GV. It then inserts that block (the 2D representation) onto the isometric line.
In short: The SKEY is the lookup key that tells the ISO engine which 2D block to draw.
Inside the ISO Symbol Editor, you will see a grid. Each cell represents a specific SKEY. For example:
Each symbol is drawn using specific rules:
IsoSymbols.dwg.GAV and rename the copy to GAG (Gear Actuated Gate).
BLOCK command to redefine GAG (ensure 'Scale uniformly' is OFF).IsoSymbols.dwg.This is the preferred method for permanent fixes.
Ball Valve, 2", Flanged).VAB to VAG if you want it to draw as a gate valve on isometrics.