Mesh

A Mesh is a geometric representation of a 3D surface, a set of connected 3D points.

In an EMesh ^{.NET Python} object, 3 points are connected to define a triangle. This kind of 3D representation is also called a triangle mesh.

A point cloud and the corresponding mesh viewed using E3DViewer ^{.NET Python}.

An EMesh ^{.NET Python} object contains a point cloud and the indexes of the vertices of all mesh triangles. It uses a metric space representation that can be generated from a depth map and that can be used to produce a ZMap.

Generation from a Depth Map

• An EMesh ^{.NET Python} object is generated from a depth map using the class EDepthMapToMeshConverter ^{.NET Python}.

• Like EDepthMapToPointCloudConverter ^{.NET Python}, this class uses a calibration model to transform the depth map pixels to 3D world positions. In addition, the depth map pixel connectivity is used to build the triangle mesh. Adjacent pixels produce surface triangles.

• Use the method EDepthMapToMeshConverter::SetCalibrationModel ^{.NET Python} to select a calibration model and the method EDepthMapToMeshConverter::Convert ^{.NET Python} to generate an EMesh ^{.NET Python} from an 8 bits or 16 bits depth map.

Generation from a ZMap

• An EMesh ^{.NET Python} object is generated from a ZMap using the class EZMapToMeshConverter ^{.NET Python}.

• Use the method EZMapToMeshConverter::SetMaxEdgeLength ^{.NET Python} to filter out the large triangles from the mesh. These large triangles occur when the colors of two neighboring pixels are very far apart.

Generation from a Point Cloud

• An EMesh ^{.NET Python} object is generated from a point cloud using the class EPointCloudToMeshConverter ^{.NET Python}.

  • The EPointCloud ^{.NET Python} is first converted to a ZMap that is then converted to an EMesh ^{.NET Python}.

• Use the method EPointCloudToMeshConverter::SetProjectionPlane ^{.NET Python} to set the projection plane.

• Use the method EPointCloudToMeshConverter::SetResolution ^{.NET Python} to specify the size of the triangles of the mesh.

• Use the method EPointCloudToMeshConverter::SetMaxEdgeLength ^{.NET Python} to filter out the large triangles from the mesh.

See also

Sample appplication

Access and Usage

• In an EMesh ^{.NET Python} object the 3D world positions are stored as an EPointCloud ^{.NET Python} (accessible through the method EMesh::GetPointCloud ^{.NET Python}). The triangle mesh is stored as an array of point indexes, where 3 consecutive indexes define a triangle.

  • The method EMesh::GetTriangleIndexes ^{.NET Python} provides a read-only access to the triangle mesh.

  • The normals are stored as an array of E3DPoint ^{.NET Python} readable through the EMesh::GetNormals ^{.NET Python} method.

• You can use either the proprietary format to save and load EMesh ^{.NET Python} objects using the EMesh::Save ^{.NET Python} and EMesh::Load ^{.NET Python} methods, or use the STL standard file format using the EMesh::SaveSTL ^{.NET Python} and EMesh::LoadSTL ^{.NET Python} methods which respectively write to and read from ASCII or binary STL files.

• You can use an EMesh ^{.NET Python} to produce a ZMap (see “Generating a ZMap”). Because an EMesh ^{.NET Python} represents a surface, the generated ZMap can show better continuity and less undefined pixels.