autocad-class-reference

name	autocad-class-reference
description	Quick reference for AutoCAD .NET API classes - 1,248 types across 28 namespaces

AutoCAD 2026 .NET API Class Reference

Quick lookup for 1,248 classes across 28 namespaces

When to Use This Skill

• Looking for AutoCAD base classes
• Finding database entities (Line, Circle, Polyline, etc.)
• Checking geometry classes
• Finding editor/application classes
• Exploring runtime services

Common Patterns

Access Database and Transaction

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Runtime;

[CommandMethod("MYCOMMAND")]
public void MyCommand()
{
    Document doc = Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
    Editor ed = doc.Editor;

    using (Transaction tr = db.TransactionManager.StartTransaction())
    {
        // Work with database objects
        BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;
        BlockTableRecord btr = tr.GetObject(bt[BlockTableRecord.ModelSpace],
            OpenMode.ForWrite) as BlockTableRecord;

        tr.Commit();
    }
}

Create Entity

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;
    BlockTableRecord btr = tr.GetObject(bt[BlockTableRecord.ModelSpace],
        OpenMode.ForWrite) as BlockTableRecord;

    // Create a line
    Line line = new Line(new Point3d(0, 0, 0), new Point3d(100, 100, 0));
    line.ColorIndex = 1; // Red

    btr.AppendEntity(line);
    tr.AddNewlyCreatedDBObject(line, true);

    tr.Commit();
}

User Input

using Autodesk.AutoCAD.EditorInput;

Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;

// Prompt for point
PromptPointOptions ppo = new PromptPointOptions("\nSelect point: ");
PromptPointResult ppr = ed.GetPoint(ppo);
if (ppr.Status == PromptStatus.OK)
{
    Point3d pt = ppr.Value;
}

// Prompt for entity
PromptEntityOptions peo = new PromptEntityOptions("\nSelect entity: ");
peo.SetRejectMessage("\nMust be a line.");
peo.AddAllowedClass(typeof(Line), true);
PromptEntityResult per = ed.GetEntity(peo);
if (per.Status == PromptStatus.OK)
{
    ObjectId lineId = per.ObjectId;
}

Full Class Index

See ../../autocad-api-reference/CLASS_INDEX.md for complete listing of all 1,248 types.

Related Skills

For Civil 3D-specific classes, use:

• /c3d-api:c3d-class-reference - Civil 3D classes
• /c3d-api:c3d-root-objects - CivilApplication/CivilDocument

For specific AutoCAD entity and API topics, use:

• /c3d-api:acad-tables - Creating and modifying AutoCAD table entities
• /c3d-api:acad-geometry - Working with geometric types (Point3d, Vector3d, curves)
• /c3d-api:acad-mtext - Creating and formatting MText entities
• /c3d-api:acad-mleaders - Creating and configuring MLeader entities
• /c3d-api:acad-fields - Working with AutoCAD field expressions
• /c3d-api:acad-dimensions - Creating dimension entities
• /c3d-api:acad-hatches - Creating hatch pattern fills
• /c3d-api:acad-blocks - Creating and inserting block references
• /c3d-api:acad-sheet-sets - Reading/writing Sheet Set (.dst) files via COM
• /c3d-api:acad-layers - Layer table, layer records, properties, and states
• /c3d-api:acad-editor-input - Editor prompts, selection sets, and filters
• /c3d-api:acad-polylines - Polyline, Polyline2d, Polyline3d entity details

Documentation

• HTML Docs: ac3d_netapi2docs/docs/AutoCAD_2026/html/index.html
• Source Code: ac3d_netapi2docs/src/AutoCAD_2026/