After a 3D mesh model is created in Skyline PhotoMesh, certain tiles may require editing, e.g. to remove a particular building that is being torn down, remove the texture of a vehicle, or to flatten surfaces and correct certain imperfections such as floating components (e.g. electric lines, lamp poles), bumps or irregular surfaces. These imperfections can be cleaned up directly in PhotoMesh using the Manual Retouch tool or in external software.
In this article:
PhotoMesh's Manual Retouch Tool
PhotoMesh’s Manual Retouch tool allows you to correct mesh imperfections, such as bumps, irregular surfaces, or floating artifacts. Using this tool, you can mark areas to be flattened or cleaned, and specify floating objects for removal. The output of the Manual Retouch tool is a feature "retouch layer" with attribute information that defines the required retouch action: clean, flatten, and retexture. When rebuilding the project, PhotoMesh uses the manual retouch layer to add a set of constraints to the reconstruction algorithms. Most of these constraints affect the mesh geometry, after which the modified model is retextured using the project’s photos or alternatively, using a specific file texture, e.g., water or grass. Polyline and polygon feature layers containing retouch geometries can also be imported in SHP, SQLite, or GPKG formats.
The Manual Retouch tool also supports the definition of water bodies. These are difficult to model accurately since the uniformity and non-static nature of water make feature identification and matching challenging. To enable PhotoMesh to model and texture a water body successfully, it can be defined by drawing or importing a corresponding polygon, which PhotoMesh uses to generate a flat surface over the specified area.
The manual retouch tool can be run either on a 3D model (the reconstruction tile’s 3D textured model or the final 3DML) or on orthophoto output. All retouch operations are listed in the Manual Retouch list.
Note: After performing manual retouch operations, all affected tiles (i.e., those intersected by the retouch polygon) must be rebuilt.
- Flatten Polygon, Flatten Profile, Remove Floating, and Remove Wire operations require rebuilding from the model step.
- Water Polygons require rebuilding from the point cloud stage.
PhotoMesh automatically determines the necessary processing and will initiate the appropriate rebuild when running the project from "Auto".
Opening the Tool
The Manual Retouch tool is opened from the Home tab > Retouch > Open Manual Retouch Toolbox.
Retouch Mode
You can run the manual retouch tool either in mesh mode - on a 3D mesh model (the reconstruction tile’s 3D textured model or the final 3DML) or in ortho mode - on orthophoto output.
Retouch Operations
The following retouch operations can be performed in mesh mode:
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Flatten Polygon (Shortcut key: f) – Remove all elements inside a defined volume, and add a flat surface in the area of the 2D polygon. For e.g., filling holes and flattening walls. The area of the 2D polygon can be textured with any of the following:
- From photos – Fill the polygon area using photos from the area.
- Remove moving cars – Fill the polygon area using only photos from the area that don’t include moving cars. This option offers a solution to undesirable reconstruction effects that can occur when capturing an area with moving cars (e.g., a car that is partially sunk in the road), since only some of the captured photos included the cars, while others did not.
- Single color – Fill the polygon area using a single color.
- Texture pattern – Fill the polygon area with a water or grass texture.
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Water Polygon (Shortcut key: t) - Create a water body by generating a flat surface over the user-defined water body:
- Smart Water – Detects and flattens water surfaces by analyzing texture colors within the drawn polygon. Even a rough outline is often sufficient. Smart Water also identifies and preserves above-water features such as boats and bridges. To apply this process, PhotoMesh downgrades the affected tiles back to the Point Cloud phase. The polygon must be drawn at an elevation as close as possible to the actual water surface. If the elevation is inaccurate, too high or too low, the water detection may fail or produce incorrect results.
- Flat Water – Begins with the Smart Water detection process but then overrides the entire polygon area, flattening it completely, regardless of whether water was detected. This ensures a uniform, artifact-free surface, even in areas where water detection may have failed.
- Flatten Profile (Shortcut key: p) – Create multiple flatten polygons by defining a profile line (usually on a roof top) and the base elevation. A flatten polygon is created for each segment of the profile line (from the line to the base elevation). This method is useful for creating retouch polygons in hard to access places, e.g., between buildings.
- Remove Floating (Shortcut key: r) – Remove all elements inside a defined volume. This option is generally used to remove floating elements that aren’t connected to the ground.
- Remove Wire (Shortcut key: w) – Remove thin elements such as power lines by drawing a polyline that marks the wire to be removed. A separate floating polygon is created for each segment of the polyline.
- Import Layer (Shortcut key: i) – Import a polyline or polygon feature layer with retouch polylines/polygons. The following layer formats are supported: .shp, sqlite, and gpkg.
The following retouch operations can be performed in orthophoto mode:
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Clean Cars (Shortcut key: c) – Remove all elements inside a defined area, and texture the drawn polygon area using only photos from the area that don’t include moving cars. This option offers a solution to undesirable effects in the reconstruction (e.g., a car that is partially sunk in the road) that can occur when capturing an area with moving cars, since only some of the captured photos included the cars, while others did not.
- Clean Edges (Shortcut key: e) – Remove artifacts along the edges of a model.
- Import Layer (Shortcut key: i) – Import a polyline or polygon feature layer with retouch polylines/polygons for cleaning edges or cars. The following layer formats are supported: .shp, sqlite, and gpkg.
Display Options
Retouch polygons can be displayed in any of the following ways:
- Volume Colorize – Mark the area for retouching by colorizing all parts of the mesh contained within the extruded polygon.
- Volume Polygon – Mark the area for retouching by displaying 3D polygons based on the extruded polygon.
- Volume No – Mark the area for retouching only with a 2D polygon.
Drawing Surface
In mesh mode, drawing surfaces 
can be used to create a surface on which to draw your retouch polygon or polyline, e.g., for a model that is not flat or missing corners. The following options are available:
- Horizontal – The surface is aligned horizontally to the area under the cursor.
- Vertical – The surface is aligned vertically to the area under the cursor.
- 3 Points – The surface is aligned to the polygon created by the three points you draw.
More about: Retouching a mesh layer in PhotoMesh >
Manual Retouch in External Software
Mesh geometry and texture edits can also be performed in external software such as Autodesk® MeshMixer, Blender, and others, and then the tiles can be imported back into PhotoMesh in order to rebuild the project.
For the full PhotoMesh – Editing Mesh Geometry and Texture manual, click here.