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Skillsspeckle-impl-autocad-civil3d

speckle-impl-autocad-civil3d

Data & analytics

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Updated 10-16 06:18

About this skill

speckle-impl-autocad-civil3d

Quick Reference

Supported Versions

Application Versions OS
AutoCAD 2022, 2023, 2024, 2025, 2026 Windows only
Civil 3D 2022, 2023, 2024, 2025, 2026 Windows only

Data Schema Hierarchy

AutoCAD:   File > Layer > Objects
Civil 3D:  File > Layer > Objects (inherits AutoCAD structure)

Publishable Content (AutoCAD)

Content Type Supported Notes
Geometry (lines, arcs, polylines, circles) Yes All standard geometry types
Hatch objects Yes Pattern and boundary preserved
Text objects (single-line, multi-line) Yes Content and formatting
Block references Yes Converted to Instance + Definition proxies
3D Solids Mesh only ALWAYS converted to Mesh — irreversible
Colors Yes Via Color proxy
Render materials Yes Via RenderMaterial proxy
XData (Extended Data) Yes Appears in properties field
Extension Dictionaries Yes Appears in properties field
Layers Yes Preserved as Collection hierarchy

Publishable Content (Civil 3D: Additional)

Content Type Supported Notes
Alignments Yes Civil3dObject with baseCurves
Corridors Yes Civil3dObject with corridor featurelines and codes
Featurelines Yes Civil3dObject with baseCurves
Pipe Networks Yes Civil3dObject with network part specifications
Surfaces (TIN/Grid) Yes Civil3dObject with surface statistics
Catchments Yes Civil3dObject with hydrological/hydraulic properties
Profiles Yes Civil3dObject with baseCurves
Property Sets Yes Organized by name in properties
Part Data Yes Entity-specific information in properties

Critical Warnings

NEVER expect 3D solids to survive the Speckle pipeline as solids. AutoCAD and Civil 3D connectors ALWAYS convert solids to Mesh geometry during publishing. This conversion is irreversible. If downstream workflows require solid geometry (boolean operations, mass properties from solids), this pipeline is NOT suitable.

NEVER assume XData or Extension Dictionary data transfers automatically to the receiving application. This data appears in the Speckle properties field and is visible in the web viewer, but the receiving connector may NOT attach it to loaded objects.

NEVER expect coordinate system alignment options in Civil 3D. Unlike the Revit connector, Civil 3D has NO reference point publishing configuration. Objects publish using the drawing's World Coordinate System.

NEVER rely on color display without verifying viewer settings. AutoCAD/Civil 3D colors require Shaded view mode in the Speckle viewer to display correctly.

AutoCAD Object Model in Speckle

Identity Mapping

AutoCAD Concept Speckle Field Purpose
Handle applicationId Stable cross-version tracking
Content hash id Deduplication (changes when data changes)
Entity type speckle_type Type discriminator

The applicationId maps to the AutoCAD Handle — a persistent hexadecimal identifier that remains stable across saves and edits. ALWAYS use applicationId for cross-version object tracking, NEVER use id.

Geometry Objects

AutoCAD geometry publishes as Speckle Geometry Objects — pure geometric primitives without semantic metadata:

  • Point, Line, Arc, Circle, Ellipse
  • Polyline, Polycurve (complex curves)
  • Mesh (including converted solids)
  • Hatch (pattern fills with boundary geometry)
  • Text (single-line and multi-line)

Block Architecture

AutoCAD blocks map to Speckle's Instance + Definition pattern:

Block Reference (Insert) → Instance Object
  - definitionId: references a Definition proxy
  - transform: 4x4 matrix (position, rotation, scale)

Block Definition → Definition Proxy (at Root Collection level)
  - name: block name
  - value: definition geometry (displayValue)
  - objects: array of applicationId strings for all instances

ALWAYS expect blocks to decompose into this two-part structure. A single Definition proxy serves all Instance objects that reference the same block.

Layer Mapping

AutoCAD layers map directly to Speckle Collections:

Drawing.dwg
└── Layer: "A-WALL"
    ├── Line object (applicationId: "1A3")
    └── Polyline object (applicationId: "1B7")
└── Layer: "S-BEAM"
    └── Mesh object (applicationId: "2C4")

Layer properties (color, linetype) are NOT preserved as layer metadata. Object-level color assignments transfer via Color proxies.

Custom Properties (XData and Extension Dictionaries)

XData and Extension Dictionaries appear in the properties dictionary of each object:

{
  "speckle_type": "Objects.Geometry.Line",
  "applicationId": "1A3F",
  "properties": {
    "ExtensionDictionary": {
      "MyCustomDict": {
        "ProjectCode": "P-2024-001",
        "Phase": "Construction"
      }
    },
    "XData": {
      "APPNAME": {
        "values": ["custom_data_1", 42.5]
      }
    }
  }
}

ALWAYS check the properties field for custom data. Extension Dictionaries are nested by dictionary name; XData is nested by registered application name.

Proxy Types (AutoCAD)

Proxy Type Purpose Stored At
RenderMaterial RGB color, opacity, metallic, roughness Root Collection
Color Hex color assignments (#RRGGBB) Root Collection
Group Functional grouping Root Collection
Definition Block geometry for reuse by Instances Root Collection

Civil 3D Object Model in Speckle

Civil3dObject

Civil3dObject extends DataObject with infrastructure-specific fields:

{
  "speckle_type": "Objects.Data.DataObject:Objects.Data.Civil3dObject",
  "applicationId": "3F7A",
  "type": "Alignment",
  "displayValue": [
    { "speckle_type": "Objects.Geometry.Mesh", "...": "visual representation" }
  ],
  "baseCurves": [
    { "speckle_type": "Objects.Geometry.Polycurve", "...": "fundamental curve" }
  ],
  "properties": {
    "PropertySets": {
      "Alignment Properties": {
        "StartStation": 0.0,
        "EndStation": 1250.0,
        "Length": 1250.0
      }
    },
    "PartData": { "...": "entity-specific data" }
  }
}

Key Distinction: displayValue vs. baseCurves

Field Content Purpose
displayValue Mesh/visual geometry What you SEE in the viewer
baseCurves Curve geometry array The FUNDAMENTAL curve of the civil entity

ALWAYS use baseCurves when you need the geometric definition of an alignment, profile, or featureline. The displayValue contains the visual representation (a mesh for most Civil 3D objects), which is NOT the same as the design curve.

Civil 3D Entity Types

Entity Type type Value Has baseCurves Key Properties
Alignment "Alignment" Yes StartStation, EndStation, Length
Profile "Profile" Yes Station/elevation data
Corridor "Corridor" No Featurelines, codes, regions
Featureline "FeatureLine" Yes 3D polyline geometry
Pipe Network "Pipe" / "Structure" Varies Network part specifications
Surface "TinSurface" / "GridSurface" No Surface statistics (area, min/max elevation)
Catchment "Catchment" No Hydrological and hydraulic properties
Parcel "Parcel" Yes Area, perimeter

Corridor Data Structure

Corridors are complex Civil 3D objects. In Speckle, corridor data includes:

  • Featureline geometry for each corridor code point
  • Corridor codes identifying each featureline's role
  • Region definitions

ALWAYS expect corridor featurelines to be accessed through properties, NOT as direct child objects. Corridors do NOT contain nested Civil3dObjects.

Property Sets

Civil 3D Property Sets publish as structured dictionaries inside properties:

{
  "properties": {
    "PropertySets": {
      "Pipe Properties": {
        "InnerDiameter": 0.3,
        "OuterDiameter": 0.35,
        "Material": "PVC",
        "SlopePercent": 2.0
      }
    }
  }
}

Each Property Set is keyed by its definition name. Values include strings, numbers, and booleans.

PropertySetDefinition Proxy (Civil 3D Only)

Civil 3D adds a fifth proxy type not present in standard AutoCAD:

Proxy Type Purpose Stored At
PropertySetDefinition Encodes Civil 3D property set structures Root Collection

This proxy stores the schema of each Property Set — field names, data types, default values. It references objects that use the property set via the standard objects array of applicationId strings.

Proxy Types (Civil 3D: Full Set)

Proxy Type Purpose
RenderMaterial Material properties
Color Hex color assignments
Group Functional grouping
Definition Block geometry reuse
PropertySetDefinition Property set schema (Civil 3D exclusive)

Publishing Workflow

AutoCAD Publishing Steps

  1. Open the Speckle connector panel in AutoCAD
  2. Select a Speckle project and model
  3. Choose objects to publish (manual selection or all visible)
  4. Click Publish — all selected objects convert to Speckle schema
  5. Layers become Collections; blocks split into Instance + Definition

Civil 3D Publishing Steps

  1. Same UI as AutoCAD (Civil 3D connector extends AutoCAD connector)
  2. Civil 3D entities automatically convert to Civil3dObject type
  3. Property Sets, Part Data, and class-specific properties captured automatically
  4. Standard AutoCAD objects (lines, blocks) publish as standard Geometry Objects

What Publishes Automatically

  • All geometry with layer assignment
  • Colors (object-level and layer-level via proxy)
  • Render materials
  • XData and Extension Dictionaries
  • Block references as Instance + Definition
  • Civil 3D: Property Sets, Part Data, network specifications, surface statistics

What Does NOT Publish

  • Layer properties (linetype, lineweight as layer metadata)
  • Layout/paper space content (model space only)
  • OLE objects
  • External references (xrefs) as linked data
  • Coordinate system/reference point configuration (Civil 3D limitation)

Loading (Receiving) Workflow

Loading Behavior

Aspect Behavior
Geometry Loads as native AutoCAD geometry (lines, arcs, meshes)
Text Loads as text objects
Blocks Loads as block references
Layer structure Flattened to match browser viewer display
Render materials Preserved
Colors Preserved via proxy
Selection management Objects loaded into their own Selection Set
Custom properties NOT loaded onto objects

Layer Flattening on Load

When loading into AutoCAD/Civil 3D, the layer structure is FLATTENED to match what the Speckle web viewer displays. Nested Collection hierarchies from other connectors (e.g., Revit's Level > Category > Type) collapse into a flat layer structure.

Selection Set

All loaded objects are placed into a dedicated Selection Set. This enables easy selection of all Speckle-loaded objects without manual picking. ALWAYS use this Selection Set for post-load operations.

Cross-Application Exchange

AutoCAD/Civil 3D as Publisher

Receiving App Result Notes
Revit Direct Shapes All geometry becomes generic models
Rhino Native geometry Lines, meshes, blocks preserved
Grasshopper Geometry/Data Objects Civil3dObject accessible as Data Object
Blender Mesh/curves Standard geometry conversion
Power BI Tabular + 3D Property Sets queryable in Power BI
Web viewer Full fidelity All properties visible, 3D visualization

AutoCAD/Civil 3D as Receiver

Source App Result Notes
Revit Geometry + layers RevitObject displayValue as meshes
Rhino Geometry + layers Direct geometry mapping
Tekla Geometry + layers TeklaObject displayValue as meshes
Any source Flat layers Hierarchy always flattened

Asymmetric Fidelity

Publishing from AutoCAD/Civil 3D preserves MORE information than loading into it. A Civil 3D alignment with Property Sets, station data, and profile geometry publishes as a rich Civil3dObject. When loaded into Rhino, it becomes geometry with properties as user strings — the native Civil 3D semantics are lost. When loaded back into Civil 3D, it becomes standard geometry, NOT a native alignment.

Reference Links

Official Sources