Plant 3D Python – Required metadata for custom valves

If you are creating your own Plant 3D valve scripts, this is a minimal working structure:

from varmain.var_basic import *  # type: ignore
from varmain.custom import *  # type: ignore


@activate( 
    Group="ValveBody",
    TooltipShort="Check valve, flanged",
    LengthUnit="mm",
    Ports="2",
    FirstPortEndtypes="SW"
)

@group("MainDimensions")  # type: ignore

@param(PN=LENGTH, TooltipShort="Nominal pressure")  # type: ignore
@param(DN=LENGTH, TooltipShort="Nominal diameter")  # type: ignore
@param(L=LENGTH, TooltipShort="Valve face-to-face length")  # type: ignore
@param(BH=LENGTH, TooltipShort="Bonnet height")  # type: ignore
@param(
    HOLES=LENGTH,
    TooltipShort="0 = no holes, 1 = show holes"
)  # type: ignore

def CPVCheckValve(
    s,
    PN=16,
    DN=50,
    L=300,
    BH=140,
    HOLES=0,
    ID="CPVCheckValve",
    **kw
):
    ...

What each part does

varmain.var_basicProvides Plant 3D parameter types such as LENGTH

varmain.customProvides decorators such as @activate, @group, and @param

@activateRegisters the custom component

Group="ValveBody"Assigns the component to the valve-body group

FirstPortEndtypesSets the default Primary End Type

Ports="2"Defines a two-port component

TooltipShortSets the script tooltip

@groupCreates a parameter group

@paramDefines editable parameters

Important must-have notes

1. Start the script name with CPV

   Otherwise, the Custom component designation may not work correctly in Spec Editor.

   Use: CPVCheckValve

2. Do not use an underscore _ directly after CPV

   Plant 3D appears to parse the script name and may expect a special suffix after the underscore.

   In my tests, a script name such as: CPV_Check_valve crashes AutoCAD Plant 3D consistently.

   Use this instead: CPVCheckValve

   The exact reason is still under investigation.

3. Use FirstPortEndtypes

   This allows the Primary End Type filters to work when creating a new component in Spec Editor and predefines the component end type.

   Example: FirstPortEndtypes="SW"

   

4. The Short Description selected in Spec Editor also affects the component behaviour

   I use: Check valve as the Short Description.

   With this value, the actuator assignment fields do not appear in Spec Editor. With another Short Description, actuator-related fields may appear.