Open a new drawing.

Before we discuss the "NET," we must understand the standard block. A standard block is a grouping of objects stored as a single unit. However, a refers to a system of interconnected blocks that share logical relationships, data links, or geometric constraints.

[CommandMethod("InsertMyBlock")] public void InsertBlockInstance() Document doc = Application.DocumentManager.MdiActiveDocument; Database db = doc.Database; using (Transaction tr = db.TransactionManager.StartTransaction()) BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable; string blockName = "Equipment_Box"; if (!bt.Has(blockName)) doc.Editor.WriteMessage($"\nError: Block 'blockName' not found. Run 'CreateMyBlock' first."); return; // Open Model Space for writing BlockTableRecord modelSpace = tr.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite) as BlockTableRecord; // Get the Object ID of the block definition ObjectId blockId = bt[blockName]; // Define insertion properties Point3d position = new Point3d(20, 20, 0); Scale3d scale = new Scale3d(1.5, 1.5, 1.5); double rotation = Math.PI / 4; // 45 degrees in radians // Create the BlockReference using (BlockReference br = new BlockReference(position, blockId)) br.ScaleFactors = scale; br.Rotation = rotation; // Append the reference to Model Space modelSpace.AppendEntity(br); tr.AddNewlyCreatedDBObject(br, true); tr.Commit(); doc.Editor.WriteMessage("\nBlock reference inserted successfully."); Use code with caution. 5. Working with Dynamic Blocks

Anonymous blocks are a powerful feature for applications needing to create temporary or hidden block definitions without cluttering the user interface.

To develop .NET plugins for AutoCAD, you typically use Microsoft Visual Studio and target the appropriate .NET Framework or .NET Core version depending on your AutoCAD release (e.g., AutoCAD 2025+ utilizes .NET Core 8).

using (AttributeReference attref = new AttributeReference())

You can also insert an entire DWG file into the current drawing using Database.ReadDwgFile followed by the Insert method. When you insert an entire drawing into another drawing, AutoCAD treats the inserted drawing like any other block reference.

Mastering AutoCAD Blocks in .NET: A Comprehensive Guide to Programmatic CAD Automation

To write AutoCAD .NET plugins, you need an Integrated Development Environment (IDE) like Visual Studio and the correct API libraries.

: Forgetting to "Commit" a transaction is the #1 reason new developers see no results in their drawing.

Blocks are rarely just static geometry. They often contain metadata called (e.g., part numbers, titles, or asset tags). Much like blocks themselves, attributes follow a split architecture:

Before diving into code, it is crucial to understand how AutoCAD internally organizes blocks. The distinction between and block references is fundamental to working with the API effectively.

Using code to handle blocks unlocks several advanced capabilities:

using (BlockTableRecord acBlkTblRec = new BlockTableRecord())

If you want to expand this logic further, let me know if you would like to:

Linq2Acad makes common tasks like deleting all block references from model space straightforward:

Dynamic blocks are a complex topic within the AutoCAD .NET API. Many developers ask whether it is possible to define dynamic properties (like linear parameters, stretch actions, visibility states) entirely through code.