Author’s Note: SKEY behavior can vary between Plant 3D versions (2018 vs 2025). Always test custom symbols in your specific version.
To 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 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 . Author’s Note: SKEY behavior can vary between Plant
In AutoCAD Plant 3D, Symbol Key (SKEY) is a four-character code that dictates how a 3D piping component is represented in 2D isometric drawings Instead, use the SkeyMap XML to map the
Conclusion SKEY in AutoCAD Plant 3D is a small but powerful mechanism linking 3D piping components to their correct isometric symbols. Properly implemented, it enforces graphic consistency, enables automation, and reduces errors in fabrication and construction handoffs. CAD administrators should manage SKEYs through disciplined catalog setup, spec mapping, ISO style configuration, and robust testing; designers should follow documented conventions so isometric outputs remain accurate, unambiguous, and useful for downstream stakeholders.
When you place a component from the Spec into your 3D model, the SKEY is written into the entity data of that object. The model now "knows" it has a "V1" sitting on that pipe.