allplan-elements

name	allplan-elements
description	This skill provides the foundational knowledge and high-level principles for defining native ALLPLAN elements (such as walls, lines, solids) within the ALLPLAN PythonParts framework.

Skill: ALLPLAN Elements

High-Level Principles

1. AllplanElement Base Class

In order to create anything within the PythonParts framework, the to-be-created-element must be an AllplanElement (or a class inheriting from it). Whether you are creating a multi-layer architectural wall, a simple 2D line, or a generic 3D solid, all classes representing these model components stem from the abstract AllplanElement base class.

The API specializes AllplanElement into distinct branches:

• Basis elements (BasisElement): Generic elements like lines, 3D-objects, hatchings, text, and library symbols.
• Architecture (ArchElement): Native architectural elements like walls, slabs, beams, columns, and negative elements like window/door openings.
• Precast (PrecastElement): Elements from the precast module (fixtures, assembly groups).
• Reinforcement (ReinfElement): Components like rebars, meshes, and couplers.

2. Composition Over Inheritance (Geometry vs. Element)

Key insight: ALLPLAN entities compose geometry — they do not are geometry. Pure geometry objects (NemAll_Python_Geometry.Point3D, NemAll_Python_Geometry.Line2D, NemAll_Python_Geometry.Polyhedron3D, NemAll_Python_Geometry.BRep3D) carry only spatial coordinates. They have no color, no pen, no layer, and cannot be placed in a drawing file on their own. Every piece of geometry must be wrapped in an AllplanElement before it can exist in the model. For example:

• A wall (NemAll_Python_ArchElements.WallElement) has a geometry acting as its axis (usually a NemAll_Python_Geometry.Line2D or NemAll_Python_Geometry.Arc2D).
• A generic 3D solid (NemAll_Python_BasisElements.ModelElement3D) has a geometry defined as a NemAll_Python_Geometry.Polyhedron3D or NemAll_Python_Geometry.BRep3D.
• A simple 2D line (NemAll_Python_BasisElements.ModelElement2D) has a geometry object defined as just a NemAll_Python_Geometry.Line2D.

Where geometry only handles spatial coordinates, the encapsulating AllplanElement defines specific components:

• NemAll_Python_BaseElements.CommonProperties: Defines the visual format representation (pen, stroke, color, layer).
• Dedicated Property Classes: An element typically pairs with property objects specific to its function (e.g., an ArchElement like NemAll_Python_ArchElements.WallElement uses NemAll_Python_ArchElements.WallProperties and NemAll_Python_ArchElements.WallTierProperties to handle thickness, tiers, and planes).

Example: Creating a simple cuboid

Pure geometry alone is not enough — it must be wrapped in an AllplanElement:

import NemAll_Python_AllplanSettings as AllplanSettings
import NemAll_Python_BasisElements as AllplanBasisElements
import NemAll_Python_Geometry as AllplanGeo

# 1. Define the pure geometry
cuboid_geometry = AllplanGeo.Polyhedron3D.CreateCuboid(1000, 500, 300)

# 2. Wrap it in an AllplanElement and assign CommonProperties
model_element = AllplanBasisElements.ModelElement3D()
model_element.GeometryObject   = cuboid_geometry
model_element.CommonProperties = AllplanSettings.AllplanGlobalSettings.GetCurrentCommonProperties()

cuboid_geometry is just a shape in space — no color, no pen, no layer. Only after it is assigned to NemAll_Python_BasisElements.ModelElement3D does it become a proper ALLPLAN element that can be placed in the drawing file.

Defining Specific Objects

Due to this framework architecture, defining objects always separates the logic of generating pure geometry from wrapping it into native ALLPLAN entities.

Detailed instructions for each element category are in the following articles:

• Basis Elements — Generic drafting and modelling elements: 2D/3D lines, solids, text, hatchings, dimension lines. Covers which API class and geometry type to use for each ALLPLAN element.
• Library Elements — Symbols, smart symbols, and fixtures from the ALLPLAN library. Covers path-based construction and how to attach them to a PythonPart.
• PythonPart Element — Parametric containers built with PythonPartUtil. Covers views, placement matrix, attributes, hierarchy (structured PythonParts, child elements, groups), and key gotchas.

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Related guides

• PythonPart Script — how to return elements from execute() using CreateElementResult.CreateElementResult
• Create a New PythonPart — end-to-end workflow