Triangle Meshes

A triangle mesh is a 3D model represented by a set of triangles connected by common edges and common vertices. If a point cloud includes a set of points, a mesh includes more information because it stores how the points are connected.

A triangle mesh therefore defines a surface in the 3D space. The mesh's edges that are owned by only one triangle are called mesh borders. A mesh is called closed if there are no borders. A mesh is called manifold if all its edges are shared by at most two triangles, and a mesh is called non-manifold if there are edges that belong to three or more triangles. A mesh is called watertight if it has no holes, or if its borders are only one closed outer polygon.

To each vertex of the mesh, a color can be associated. Each mesh's triangle is rendered with a gradient of the three colors of its vertices. The rendering color may depend also on the triangle's inclination with respect to the light source.

Reconstructor® has various techniques for generating and editing meshes. Each triangle mesh item can contain more than one submesh.


Actions available from meshes' context menu

  • Meshing->Compute normals: computes or updates the triangles' normals for the mesh.
  • Meshing->Invert winding: inverts the ordering of the vertexes for each triangle, so the surface is flipped to the opposite side and also the normals are inverted.
  • Meshing->Compute area: r eturns the mesh area as sum of the areas of all the mesh's triangles.
  • Meshing->Compute volume from Z=0 plane: returns the volume resulting from integrating the mesh on the XY plane of the current UCS. Mesh triangles below the XY plane will result in zero volume.
  • Meshing->Get mesh borders as polyline: creates a new polyline containing the mesh's borders, and adds it to the project. 
  • Meshing->Make single mesh: to cluster in a single mesh an arbitrary set of triangle meshes.
  • Meshing->Convert to point cloud: create an unstructured point cloud from the vertexes of the mesh using the color attribute of the mesh.
  • Meshing->Mesh editor: opens the mesh editor dialog.
  • Photo&Color->Sample texture at vertexes: sample the color of texture (if available) at the vertexes of the mesh and store as the color attribute of the mesh.
  • Photo&Color->Create texture map: compute a blended texture map for the mesh from the projectors.



Meshes' editable properties

  • Color ID: False color that you can activate with Screen settings -> Color by ID command
  • Draw coordinate frame: if true, draw the local coordinate frame
  • Point size: if draw geometry is set to points, they are draw with this size
  • Draw texture: if available, the texture is loaded and rendered
  • Draw light: if the normals are valid, the triangles are rendered with smooth shading
  • Cull face: if true, the triangles are rendered only if the normal faces the view direction, and backface triangles are hidden. If False both sides of the mesh are visible
  • Draw geometry: select flat, wireframe (only edges), or only  vertexes (points) to display them


Advanced Options

Triangle meshes data storage

Data is stored in an XML description file + pure binary vector files subdivided in folders for each submesh. The file extension of the binary data specifies the format, where data.NT: N=num of components (1,2,3,4…), T=data type (byte, short, word, half, float, double). If a mesh is called myMesh, a typical way of storing it will use the following files in the project folder:

  • Meshes/myMesh.rtm
  • Meshes/myMesh_rtm/submesh/vertexes.3f
  • Meshes/myMesh_rtm/submesh/triangles.3i
  • Meshes/myMesh_rtm/submesh/...

See also Meshing techniques and Mesh editing.