EXScan Post Processing Tools

This article has been written based on software EXStar v1.0.5.0, EXScan H v1.1.0.1, EXScan HX v1.3.0.3.

EXScan software includes some tools for mesh editing, which can be used to both post process meshes produced by scanned data or any mesh (STL, OBJ or PLY)  imported into the software.

In this article we are going to take a look at all these tools available under the Post Processing tab and provide detailed examples of their effect.

In the EXScan software, head over to the Post Processing tab, to access the mesh editing tools.

1. Texture

Texture is available only if the mesh contains texture data.

This tool allows the edit of the brightness and contrast of the texture file.

Original file:

After Texture edit:

Set values from -100 to 100 for both parameters to correct the colour data.

Click on 'Confirm' to save the changes or 'Cancel' to discard them.

2. Simplification

Simplification reduces the size of the mesh universally by reducing the number of triangles it consists of.

Meshing the scanned data, specially for high resolution scans, might result in meshes containing thousands or millions of triangles, which means heavy files to deal with.

Simplifying the data reduces the size of the files as much as needed.

As the slider is set to different values for simplification (from 0 to 100%) an estimation of the size of the file and the number of polygons is provided.

Select the desired value for the simplification and click on 'Apply' to carry out the operation.

The mesh from the image above has been simplified from 1.183.108 triangles to 177.466, which means decreasing its size from 56 to 8.5 MB.

Click on 'Confirm' to keep the changes or 'Cancel' to discard them.

High level of simplification or iteratively simplifying the data may cause loss of detail:

3. Mesh Optimization

The mesh optimization tool remeshes the data by adding more triangles to curvature regions.

Select a value between 0 and 100%. Click on 'Apply' to carry out the operation.

Then click on 'Confirm' to keep the edit or 'Cancel' to discard it.

For the mesh from the previous example, a Mesh Optimization of 100% supposes increasing the number of polygons from the original 1.183.108 to 1.193.489 triangles.

At first glance, it might look like nothing really changed.

However, this tool is to be used together with Simplification.

Given that, after the Mesh Optimization, the curvature regions have a higher density of polygons, the simplification operation will affect differently:

Therefore, this tool adapts the mesh to its geometry: the triangle size is defined according to the geometry of each region.

Flat regions can be represented by bigger triangles. Curvature regions will require smaller triangles to maintain the detail.

The usage of triangles is therefore optimized to represent the original mesh in a lighter, faithful and accurate manner.

4. Smooth

Scan data is a set of measurements that, like any other measurement system, has certain noise.

The Smooth tool compensates this noise by moving points to statistically correct locations, within certain range, defined by the value set in the tool slider.

Select a value from 0 to 100% and click on 'Apply'. The software will move the points of the mesh to reduce its noise.

Click on 'Confirm' to keep the changes. Click on 'Cancel' to discard them.

5. Remove Small Floating Parts

This tool applies when the mesh consists of many disconnected mesh volumes or surfaces or mesh islands.

From 0 to 100%, where 100% is the size of the largest mesh island, smaller islands are to be removed.

In the example below, as a result of scanning the object lying on the floor, parts of the latter have been scanned.

The Remove Small Floating Parts tool eases the process of cleaning the mesh, by keeping only the mesh island with higher number.

From 0 to 100%, select a value and click on 'Apply' to start removing the small floating parts.

Click on 'Confirm' to keep the edit. Click on 'Cancel' to discard it.

6. Auto Hole Filling

For unwatertight meshes, the Auto Hole Filling tool allows the automatic filling of the holes based on their edge topology.

For the filling type, one of the three techniques listed below can be selected:

  • Curvature: Specifies that the new mesh that fills the selected holes must match the curvature of the surrounding mesh.
  • Tangent: Specifies that the new mesh that fills the selected holes must match the curvature of the surrounding mesh, but with more tapering than the Curvature technique.
  • FlatSpecifies that the new mesh that fills the selected holes is generally flat.

The perimeter field lets the user define the largest perimeter of the holes to be filled. For the example below, only holes with a perimeter of 200 or less millimetres are filled. Select a high value to make sure all the holes are filled.

When clicking on 'Apply' all holes meeting these settings are filled with the selected Filling Type.

Select 'Confirm' to keep the edit. Select 'Cancel' to discard the changes.

7. Manual Hole Filling

This tool identifies the holes of the mesh and highlight their edges in green.

Choose the filling type (Curvature, Tangent or Flat) and select the holes to be filled.

On the top of the screen, a counter displays the number of detected holes and how many of them have been filled. It updates as holes are filled:

Click on 'Confirm' to keep the edit. Click on 'Cancel' to discard it.

8. Texture Remapping

Textured meshes, after applying post processing operations (such as Hole Filling or Simplification), might require a texture remapping. Otherwise texture data may not apply well on the mesh surface.

Letting the software remap the texture on the edited mesh will not only repair the textures projection on the surfaces, but will also apply texture data on the filled holes, where it was missing before.

The Texture Remapping tool is found on the right side of the screen, under the following symbol:

Click on it and select 'OK' to let the software remap the textures on the edited mesh:

Remapping the texture will rearrange the projection of the images captured by the scanner on the mesh and heal the result:

On the other hand, the checkbox for Texture Layout Optimization will process the texture file to produce an unwrapped UV map of the texture data. This is convenient to postprocess the texture in a 3rd-party software.

Simply check the Texture Layout Optimization checkbox to enable the tool:

After exporting the data as OBJ, the differences between the corresponding JPEG files can be observed:

Note: The texture optimization tools are only available for meshes produced by the EXScan software, whose project data is available. Imported textured meshes can't be processed.

9. Flip Normal

The Normal vector defines which face of a surface is the front face and which is the back face.

The EXScan software displays the front faces with a bright blue and the back faces with a darker tone of blue:

For certain applications or in some 3rd-party software the direction of the normal vector is significant. Therefore the option to flip the front and back faces is provided.

For meshes containing more than one mesh islands it is possible to define only one domain to be flipped.

Click on 'Confirm' to keep the edit. Click on 'Cancel' to discard it.

10. Cutting Plane Tool

This is a tool that allows intersecting the mesh with a plane, fill it at the intersection and align it to the CSYS in a quickly manner.

For detailed information on the use of this tool, please take a look at the following solution article:

The Cutting Plane Tool (Post Processing)

11. Mirror

The Mirror tool allows mirroring the mesh through a plane defined by the user.

Load a mesh and select the Mirror tool.

Optionally check the checkbox to keep the initial mesh. Otherwise, the original mesh will be deleted after the operation.

While holding the ⇧ SHIFT key, use the Left Mouse Button to draw a line. This will define the mirroring axis.

Finally, click on 'Apply'. The symmetrical mesh is generated.

Click on 'Confirm' to keep the edit. Click on 'Cancel' to discard it.

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