Visualize Mesh or Point Cloud Distances

This algorithm performs point cloud-to-point cloud, mesh-to-point cloud, point cloud-to-mesh and mesh-to-mesh 3d surface comparison.

Input

Two meshes, or two point clouds, or a point cloud and a mesh.

Output

A color coded visualization of the distance of the mesh/point cloud to the reference mesh/point cloud as well as some statistics of the involved distances. Furthermore there is an option to export “reduced” versions of the involved point clouds/meshes, that were used for the computation, as well as the calculated measures.

Description

When passing in data to the algorithm, the first data is always the query data and the second is the reference data. This means for every point in the query data we are looking for the nearest point (Distance type: Point-to-point) or nearest face (Distance type: Point-to-surface) of the reference data. Accordingly, the first chosen mesh/point cloud is displayed with the colored vertices, where color depends on the distance. The histogram shows the distribution of the distances.

The avaiable options for the Distance type are:

  • Point-to-point. Computes vertex-wise distances between the two data.
  • Point-to-surface. Computes vertex to face distances between the two data. This type is unavailable for mesh/point cloud to point cloud distance computation. User can choose between signed and unsigned distances with the help of checkbox signed distance. The sign of the distance depends on the face normal (i.e. which side of the surface the query point is located on). In case of signed distances, a user has an option to display a symmetric range of distances with the help of the checkbox symmetric range.

A user can change the Range of interest. This parameter represents the selected range of points, which are sorted according to the distance. See the following image displaying an example with the point cloud which has 10 points, which are then sorted according to the distance.

../../_images/PointDist.png

If, for example, the range of interest is set from 10% to 70%, points with IDs 9, 0, 2 and 3 would be removed from consideration when the button Recompute is pressed. This means that the visualization of the distances would be rendered only for the remaining points. Also, distance statistics (average, mean and others) would be computed only for the remaining points. A user can choose to export a point cloud or a mesh with the removed points by clicking Export reduced mesh/pointcloud button.

../../_images/PointDistROI.png

One can specify a range that is displayed and referred to as Displayed range. Or a range of percentiles such that the distance values are clipped on the outside of the range, referred to as Saturation range. The Saturation range (and the Displayed range) can also be modified by dragging triangular colorful (and grey) handles located at the corners of the histogram.

If the input data contains a manifold mesh, the algorithm will also compute its volume. If the input contains two manifold meshes, the Dice coefficient can be computed by pressing the button Compute Dice Coefficient.