Mesh Offset

Example of mesh offset

• C++

  #include <MRMesh/MRBox.h>
  #include <MRMesh/MRMesh.h>
  #include <MRMesh/MRCube.h>
  #include <MRMesh/MRMeshSave.h>
  #include <MRMesh/MRRegionBoundary.h>
  #include <MRVoxels/MROffset.h>
   
  #include <iostream>
   
  int main()
  {
      // Create mesh
      MR::Mesh mesh = MR::makeCube();
   
      // Setup parameters
      MR::GeneralOffsetParameters params;
      // calculate voxel size depending on desired accuracy and/or memory consumption
      params.voxelSize = suggestVoxelSize( mesh, 10000000.f );
      if ( !MR::findRightBoundary( mesh.topology ).empty() )
          params.signDetectionMode = MR::SignDetectionMode::HoleWindingRule; // use if you have holes in mesh
   
      // Make offset mesh
      float offset = mesh.computeBoundingBox().diagonal() * 0.1f;
      auto meshRes = MR::generalOffsetMesh( mesh, offset, params );
      if ( !meshRes.has_value() )
      {
          std::cerr << meshRes.error() << std::endl;
          return 1;
      }
   
      // Save result
      if ( auto saveRes = MR::MeshSave::toAnySupportedFormat( *meshRes, "mesh_offset.stl" ); !saveRes )
      {
          std::cerr << saveRes.error() << std::endl;
          return 1;
      }
   
      return 0;
  }

  Source mesh
  
  After offset
  
• Python

  import meshlib.mrmeshpy as mrmeshpy
  import sys
   
  # Load mesh
  mesh = mrmeshpy.loadMesh("mesh.stl")
   
  # Setup parameters
  params = mrmeshpy.OffsetParameters()
  params.voxelSize = mesh.computeBoundingBox().diagonal() * 5e-3 # offset grid precision (algorithm is voxel based)
  if mrmeshpy.findRightBoundary(mesh.topology).empty():
      params.signDetectionMode = mrmeshpy.SignDetectionMode.HoleWindingRule  # use if you have holes in mesh
   
  # Make offset mesh
  offset = mesh.computeBoundingBox().diagonal() * 0.05
  try:
      result_mesh = mrmeshpy.offsetMesh(mesh, offset, params)
  except ValueError as e:
      print(e)
      sys.exit(1)
   
   
  # Save result
  mrmeshpy.saveMesh(result_mesh, "offsetMesh.stl")

  Source mesh
  
  After offset
  
• C

  #include <MRCMesh/MRAffineXf.h>
  #include <MRCMesh/MRBox.h>
  #include <MRCMesh/MRCube.h>
  #include <MRCMesh/MRMesh.h>
  #include <MRCMesh/MRMeshPart.h>
  #include <MRCMesh/MRMeshSave.h>
  #include <MRCMesh/MRString.h>
  #include <MRCMesh/MRVector3.h>
  #include <MRCMisc/expected_MR_Mesh_std_string.h>
  #include <MRCMisc/expected_void_std_string.h>
  #include <MRCMisc/std_string.h>
  #include <MRCVoxels/MROffset.h>
   
  #include <math.h>
  #include <stdio.h>
  #include <stdlib.h>
   
  #define APPROX_VOXEL_COUNT 10000000.f
   
  int main( void )
  {
      int rc = EXIT_FAILURE;
   
      // Create mesh
      MR_Vector3f size = MR_Vector3f_diagonal( 1.f );
      MR_Vector3f base = MR_Vector3f_diagonal( -0.5f );
      MR_Mesh* mesh = MR_makeCube( &size, &base );
   
      // offset functions can also be applied to separate mesh components rather than to the whole mesh
      // this is not our case, so the region is set to NULL
      MR_MeshPart* inputMeshPart = MR_MeshPart_Construct( mesh, NULL );
   
      // Setup parameters
      MR_OffsetParameters* params = MR_OffsetParameters_DefaultConstruct();
      // calculate voxel size depending on desired accuracy and/or memory consumption
      MR_BaseShellParameters_Set_voxelSize( MR_OffsetParameters_MutableUpcastTo_MR_BaseShellParameters( params ), MR_suggestVoxelSize( inputMeshPart, 10000000.f ) );
      MR_Box3f bbox = MR_Mesh_computeBoundingBox_1( mesh, NULL );
      float offset = MR_Box3f_diagonal( &bbox ) * 0.1f;
   
      // Make offset mesh
      MR_expected_MR_Mesh_std_string* outputMeshEx = MR_offsetMesh( inputMeshPart, offset, params );
      MR_MeshPart_Destroy( inputMeshPart );
      MR_OffsetParameters_Destroy( params );
   
      MR_Mesh* outputMesh = MR_expected_MR_Mesh_std_string_GetMutableValue( outputMeshEx );
   
      if ( !outputMesh )
      {
          fprintf( stderr, "Failed to perform offset: %s", MR_std_string_Data( MR_expected_MR_Mesh_std_string_GetError( outputMeshEx ) ) );
          goto fail_offset;
      }
   
      // Save result
      MR_expected_void_std_string* saveEx = MR_MeshSave_toAnySupportedFormat_3( outputMesh, "mesh_offset.stl", NULL, NULL);
      if ( MR_expected_void_std_string_GetError( saveEx ) )
      {
          fprintf( stderr, "Failed to save mesh: %s\n", MR_std_string_Data( MR_expected_void_std_string_GetError( saveEx ) ) );
          goto fail_save;
      }
   
      rc = EXIT_SUCCESS;
  fail_save:
      MR_expected_void_std_string_Destroy( saveEx );
  fail_offset:
      MR_expected_MR_Mesh_std_string_Destroy( outputMeshEx );
      MR_Mesh_Destroy( mesh );
      return rc;
  }

  Source mesh
  
  After offset
  
• C#

  using System.Globalization;
  using System.Reflection;
   
  public class MeshOffsetExample
  {
      public static void Run(string[] args)
      {
          if (args.Length != 2)
          {
              Console.WriteLine("Usage: {0} MeshOffsetExample OFFSET_VALUE", Assembly.GetExecutingAssembly().GetName().Name);
              return;
          }
   
          try
          {
              float offsetValue = float.Parse(args[1],
                        System.Globalization.NumberStyles.AllowDecimalPoint,
                        CultureInfo.InvariantCulture);
   
              // Load mesh
              var mesh = MR.MeshLoad.FromAnySupportedFormat("mesh.stl");
   
              MR.MeshPart mp = new(mesh);
   
              // Setup parameters
              MR.OffsetParameters op = new();
              op.VoxelSize = MR.SuggestVoxelSize(mp, 1e6f);
   
              // Make offset mesh
              var result = MR.OffsetMesh(mp, offsetValue, op);
   
              // Save result
              MR.MeshSave.ToAnySupportedFormat(result, "mesh_offset.stl");
          }
          catch (Exception e)
          {
              Console.WriteLine("Error: {0}", e.Message);
          }
      }
  }

  Source mesh
  
  After offset