From this menu it's possible to apply the selected mesh filter to a mesh in the workspace.


Decimation: allows selecting the referred mesh from the drop-down menu and setting the number of corresponding vertices. The mesh will be regenerated by decimating the number of vertices with the specified maximum value. You can ask the software to:


  •   Preserve the boundaries: with this option, the vertices borders are never decimated. Therefore, it will allow having an edge equal to the starting mesh; the disadvantage is that the border remains much denser at the inner part's expense, resulting in fewer points and less detail.


  •  Filter only selected triangles: with this option, you can decimate just the mesh areas previously selected with the selection tools.


Densification: select the reference mesh with the drop-down menu and the desired number of vertices. The mesh will be regenerated by densifying the number of vertices with the specified maximum value.
You can either apply the filter to the mesh you have selected or clone it and filter the mesh copy.


Retopology: This filter allows you to optimize the mesh topology. Triangles will be simplified and Zephyr will try to generate larger triangles where possible. The greater the optimization factor, the larger the size of the generated triangles. Please, note the filter may cause a loss of mesh detail, especially where there are geometries with well-defined edges.


Laplacian smoother: reduces the mesh noise and does not keep sharp edges. The more iterations are inserted, the more smooth the mesh will be. This filter is suitable for non-edged subjects (e.g., human body datasets).


Bilateral smoother: the filter allows to smooth selected mesh with the appropriate drop-down menu, and it reduces noise by improving and emphasizing edges where it is possible. This filter is suitable for architecture and construction scenarios.


Photoconsistency Based Optimization: this is a kind of filter that, based on photos, optimizes the surface of the model to make it as much consistent as possible with the starting images, through a minimization process, where at each iteration, the surface is modified in such a way as to reduce the error of reprojection of one image on the other. This allows obtaining a much more detailed rendering of the surface, thus increasing its accuracy.





Here below, a detailed analysis of how to change these settings; in brackets ( ), you will find the default values:


  • Image resolution (50): controls the image’s scale resolution used internally by the photoconsistency algorithm. If you already have suitable initial geometry, it is reasonable to run the photoconsistency with a high resolution (50% – 75%). If the input is of poor quality, it is advised to leave a low resolution (25%).


  • Hierarchical subdivision (1): if this value is greater than zero, the photoconsistency algorithm will be sequentially applied more times, automatically adjusting the image resolution and the iteration number. This means that the same results can be obtained by running the same algorithm multiple times with different and appropriate settings.


  • Reprojection area (20): controls the size that every triangle will try to obtain at the end of the photoconsistency process. Given a triangle, its final reprojection area (in pixels) to the nearest camera will tend to get near to the specified value. Lowering this value will make a denser mesh: the final mesh will then have a variable level of detail, with a higher vertex point cloud corresponding to those areas viewed by nearer cameras. In most cases, the default value will work well; in case you are dealing with a mesh that is already very good (for example, one that has already finished a photoconsistency step). This parameter can be lowered to get more detail; instead, it can be raised in very noisy meshes and low-quality images.


  • Edge filter (0): this parameter is used to emphasize edges; the more the mesh is angular (buildings, objects, etc.), the more you can increase this value. Usually, it can be kept at a value of 0.5.


  • Enhance filter (0): it is a post-processing method that can generate “fake details” by increasing the number of mesh triangles. Depending on the result you want to obtain and the photo’s quality, you need to carefully adjust the slider to avoid creating additional noise instead of additional details.


  • Update colors: calculate vertex colors according to cameras. It recalculates the colors each time after making the photoconsistency. The flag can disable for the test, and the colors can be recalculated later.



Ground Extraction Filter: allows the automatic extraction of the terrain from a mesh to create a 3D Digital Terrain Model (DTM) and eliminate everything above, such as trees and houses. Users can select the mesh and set the following parameters:


  • Scene: suggests filtering the type of scenario that has been reconstructed in 3D.


  • Resolution: refers to the grid size of cloth that is used to cover the terrain. The bigger the resolution, the coarser the DTM.


  • Height threshold: refers to a threshold to classify the point clouds into the ground and non-ground parts based on the distances between points and the simulated terrain.


The “preview” button will highlight the terrain elements as green and non-terrain elements as red. Optionally, you can use a selection to force non-terrain regions.



Update colors: this filter allows re-computing mesh colors:


  • From images: (e.g., to change the workspace pictures if you are dealing with multispectral imagery).


  • By elevation: it updates the colors according to the points’ elevation. A list of color maps will allow you to pick among several color palettes.


  • By normals: using normal maps from the dataset images.


  • Uniform: choosing one specific color from a color palette.


  • By curvature: different sets of colors can be applied according to the local geometry, which means the color varies depending on whether the area is flat, angular, or curved.



Fill Holes Selective or WaterTight: it allows to automatically fill and close holes in the meshes. There are two modes are available:


  •  WaterTight mode: allows automatically filling all the holes at once.


  • Selective mode: allows filling the holes manually in the selection window. You can select a specific hole by:


     - Number: choosing it directly in the 3D workspace with the pick hole button, or the corresponding number (the hole will be highlighted with an outline in the workspace).  

     - Size: defining the size threshold using the dedicated slider.


The color of the triangles that will close the hole will most likely be wrong when the missing visibility of the point from the camera will behave in a degenerated way (and it is impossible to identify the color of something that is not seen by any picture). The Selective mode allows you to close single holes faster, but it may not work for complex cases, which we recommend using the WaterTight mode.



Cut with bounding box: by changing the bounding box’s size created by the mesh, it can be adjusted to cut unnecessary parts and exclude them outside the bounding box.


Cut with plane: this function allows you to cut the mesh sharply with a plane, regenerating the triangles on the edge where cut.