Block Reference Example

This example demonstrates creating and using block references with layer-based colors. It shows how to define blocks, add elements to them, and create references with attributes. 

using CadSDK;
using CadSDK.Elements;
using CadSDK.Enums;
using CadSDK.Geometry;
using System.Numerics;

// Create a drawing session
var session = new DrawingSession
{
    ExportFormat = ExportFormat.DWG,
    CadVersion = CadVersion.Cad2018
};

// Define layers
var blockLayer = new Layer { Name = "TestLayer_Blocks", ColorARGB = AciColors.Yellow };
var geoLayer = new Layer { Name = "TestLayer_BlockGeometry", ColorARGB = AciColors.GrayishCrimson2 };
session.AddLayer(blockLayer);
session.AddLayer(geoLayer);

// Block definition demonstrating layer colors
var blockDef1 = new BlockDefinition()
{
    Name = "CadSDK_Test_Block_001",
    ReferencePoint = Vector3.Zero,
    LengthUnit = LengthUnit.Millimeters
};
session.AddBlock(blockDef1);

// Elements in block using layer colors and ByBlock
var line1 = new Line(new Vector3(-5, -5, 0), new Vector3(5, 5, 0))
{
    LayerName = geoLayer.Name
};
var circle1 = new Circle(Plane3D.WorldXY, Vector3.Zero, 5f)
{
    ColorMethod = PropertyMethod.ByBlock
};
blockDef1.AddElement(line1);
blockDef1.AddElement(circle1);

var attDef1 = new AttributeDefinition(new Vector3(0, -10, 0), "PART_NUMBER", "Enter Part Number:", "PN-000", 2f, Plane3D.WorldXY)
{
    LayerName = geoLayer.Name
};
blockDef1.AddElement(attDef1);

// Block reference using layer color
var blockRef1 = new BlockReference(blockDef1.Name, new Vector3(100, 0, 0))
{
    LayerName = blockLayer.Name
};
blockRef1.Attributes.Add("PART_NUMBER", "PN-123");
session.AddElement(blockRef1);

// Export the drawing
// You can signup and get your free API key
string apiKey = "your-api-key"; // Get your free API key from the dashboard
string outputPath = "drawing.dwg";
await session.ExportAndSaveAsync(apiKey, outputPath);
# Coming soon...

Key Points

  • Block references allow reuse of geometry:
    • First define a BlockDefinition containing elements
    • Then create BlockReference instances to place it in the drawing
  • Block elements can use different color methods:
    • PropertyMethod.ByLayer: Inherit color from layer
    • PropertyMethod.ByBlock: Inherit color from block reference
    • PropertyMethod.Custom: Use own color
  • Attributes allow for variable text in blocks:
    • Define attributes using AttributeDefinition in block definition
    • Set values using Attributes dictionary in block reference
  • Each block definition needs a unique name and reference point.
  • Block references can be placed at different positions with their own properties.