ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Geometry Namespace / Multipatch Class / GetPatchStartPointIndex Method
The index of the patch. Must be greater than or equal to zero and less than PartCount.
Example Version

GetPatchStartPointIndex Method
Gets index of the start point into this multipatch's point collection for the specified patch (part).
Syntax
public int GetPatchStartPointIndex( 
   int patchIndex
)

Parameters

patchIndex
The index of the patch. Must be greater than or equal to zero and less than PartCount.

Return Value

The index of the start point for the patch.
Exceptions
ExceptionDescription
The patch index must be >= 0.
The patch index must be less than the number of patches (parts) in the multipatch.
Remarks
Use this method along with the GetPatchPointCount method and the Points property to get the points for this patch.
Example
Multipatch Properties
// standard geometry properties
bool hasZ = multipatch.HasZ;
bool hasM = multipatch.HasM;
bool hasID = multipatch.HasID;
bool isEmpty = multipatch.IsEmpty;
var sr = multipatch.SpatialReference;

// number of patches (parts)
int patchCount = multiPatch.PartCount;
// number of points
int pointCount = multiPatch.PointCount;

// retrieve the points as MapPoints
ReadOnlyPointCollection points = multipatch.Points;
// or as 3D Coordinates
IReadOnlyList<Coordinate3D> coordinates = multipatch.Copy3DCoordinatesToList();


// multipatch materials
bool hasMaterials = multiPatch.HasMaterials;
int materialCount = multiPatch.MaterialCount;


// multipatch textures
bool hasTextures = multiPatch.HasTextures;
int textureVertexCount = multiPatch.TextureVertexCount;

// normals
bool hasNormals = multiPatch.HasNormals;


// properties for an individual patch (if multipatch.PartCount > 0)
int patchPriority = multiPatch.GetPatchPriority(patchIndex);
PatchType patchType = multiPatch.GetPatchType(patchIndex);

// patch points
int patchPointCount = multiPatch.GetPatchPointCount(patchIndex);
int pointStartIndex = multiPatch.GetPatchStartPointIndex(patchIndex);
// the patch Points are then the points in multipatch.Points from pointStartIndex to pointStartIndex + patchPointCount 

// if the multipatch has materials 
if (hasMaterials)
{
  // does the patch have a material?  
  //   materialIndex = -1 if the patch does not have a material; 
  //   0 <= materialIndex < materialCount if the patch does have materials
  int materialIndex = multipatch.GetPatchMaterialIndex(patchIndex);


  // properties for an individual material (if multipatch.MaterialCount > 0)
  var color = multipatch.GetMaterialColor(materialIndex);
  var edgeColor = multipatch.GetMaterialEdgeColor(materialIndex);
  var edgeWidth = multipatch.GetMaterialEdgeWidth(materialIndex);
  var shiness = multipatch.GetMaterialShininess(materialIndex);
  var percent = multipatch.GetMaterialTransparencyPercent(materialIndex);
  var cullBackFace = multipatch.IsMaterialCullBackFace(materialIndex);

  // texture properties
  bool isTextured = multipatch.IsMaterialTextured(materialIndex);
  if (isTextured)
  {
    int columnCount = multipatch.GetMaterialTextureColumnCount(materialIndex);
    int rowCount = multipatch.GetMaterialTextureRowCount(materialIndex);
    int bpp = multipatch.GetMaterialTextureBytesPerPixel(materialIndex);
    TextureCompressionType compressionType = multipatch.GetMaterialTextureCompressionType(materialIndex);
    var texture = multipatch.GetMaterialTexture(materialIndex);
  }
}

// texture coordinates (if multipatch.HasTextures = true)
if (hasTextures)
{
  int numPatchTexturePoints = multiPatch.GetPatchTextureVertexCount(patchIndex);
  var coordinate2D = multiPatch.GetPatchTextureCoordinate(patchIndex, 0);

  ICollection<Coordinate2D> textureCoordinates = new List<Coordinate2D>(numPatchTexturePoints);
  multiPatch.GetPatchTextureCoordinates(patchIndex, ref textureCoordinates);
}


// patch normals (if multipatch.HasNormals = true)
if (hasNormals)
{
  //  number of normal coordinates = multipatch.GetPatchPointCount(patchIndex)
  Coordinate3D patchNormal = multipatch.GetPatchNormal(patchIndex, 0);
  ICollection<Coordinate3D> normalCoordinates = new List<Coordinate3D>(patchPointCount);
  multipatch.GetPatchNormals(patchIndex, ref normalCoordinates);
}

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also