VCGLibForParaview

VCGLibForParaview is an university project for the Scientific and Large Data Visualization course of the University of Pisa.

The main goal is bringing the VCG (http://vcg.isti.cnr.it/vcglib/) functionalities inside Paraview but also providing a set of utilities to make really confortable moving between the VCG world and the VTK one or viceversa. The result is a Paraview plugin with the many advanced VCG algorithms encapsulated in single place and completely available through the pipeline-based framework.

Table of Contents

• Installation
• Documentation
  • Hausdorff Distance
    • Inputs
    • Outputs
    • Properties
  • Uniform Random Sampling
    • Inputs
    • Outputs
    • Properties
• Contributing
  • Filters
• License

Installation

Once downloaded the source code, go into the directory

cd VCGLibForParaview

and get all the dependencies by running:

git submodules update --init

this starts the download of the VCGLib from the develop branch.

In order to build the Paraview plugin, make a directory (outside the source directoy preferably) where the MakeFile will be generated:

mkdir ../VCGLibForParaview_build && cd ../VCGLibForParaview_build

then run ccmake from inside the current directoy specifing as argument the source directory

ccmake ../VCGLibForParaview

Generally all the configurations are set correctely, but if you want build the plugin in debug mode you have to set the option CMAKE_BUILD_TYPE to Debug. After this type c (configure) and g (generate the makefile and exit).

Finally build the plugin running:

make

and inside the directory the libVCG shared library should be appeared.

Now open Paraview and load the library through the Plugin Manager (Tools > Manage Plugin) by clicking in Load New... and selecting the shared library. If no errors are occured, the entry VCG is shown with status Loaded and in the Filters section the VCG group is added with all the filters of this plugin as well.

Documentation

Since the actual small numbers of the functionalities available through the puglin, the relative documentation about them is exposed here waiting for future contributes to move all into a wiki's page.

Hausdorff Distance

Hausdorff Distance is a filter that given two meshes, one as source and the other as target (both of type VTKDataSet to be as general as possible) it returns the Hausdorff Distance as field data of the output along further data depending on how the filter properties have been set. The filter provides two output ports:

• PointCloudSource: the sample points generated over the source's surface
• PointCloudTarget: the sample points generated over the target's surface

both of them contain those points made by the sampler to the computation of the Hausdorff Distance. Moreover PointCloudSource keeps the output fields data so they can be propagated over the pipeline.

Inputs

• Source Data
  • Type: vtkDataSet
  • Description: the source mesh
• Target Data
  • Type: vtkDataSet
  • Description: the target mesh

The filter works surfing over triangular faces, so in order to apply this filter the Paraview's Triangulate filter has to be considered if your mesh may be composed by different types of faces.

Outputs

• DistanceRange
  • Type: double[3]
  • Description: array where the first item is the minimum distance from source to target, the second item is the mean distance from source to target and the third one is the maximum distance from source to target (equivalent to HausdorffDistance).
• HausdorffDistance
  • Type: double
  • Description: the value of the Hausdorff Distance computed from the source mesh to target mesh.
• RMSDistance
  • Type: double
  • Description: Route Mean Square Error value.

Properties

• Diagonal Percent
  • Type: double
  • Range: [0,1]
  • Default: 0.1
  • Description: fraction of the source bounding box diagonal length that a point of the target surface can be far at most from a point of the source surface to be consider as valid point during the Hausdorff Distant computation.
• Number of Samples
  • Type: int
  • Default: 10000
  • Description: number of samples generated by the sampler over both the source and target's surfaces (sometimes can be less than the set number).
• Sample Edge
  • Type: bool
  • Default: false
  • Description: run the sampling process also over the source's edges.
• Sample Vert
  • Type: bool
  • Default: false
  • Description: run the sampling process also over the source's vertexes.
• Save Sample
  • Type: bool
  • Default: true
  • Description: store the sample points generated over both the source and target surfaces into the PointCloudSource and the PointCloudTarget respectively.

Uniform Random Sampling

Inputs

Outputs

Properties

Contributing

Paraview allow you to extend it by Filters but also Readers and Writers, as explain here Paraview/Plugin HowTo. Since the actual version of the plugin exports just Paraview's filters, only they will be covered by this section.

Filters

It's highly recommended reading the Paraview documentation Adding a Filter on the Paraview Wiki page Plugin HowTo, since the following instruction steps are derived from those ones described in that page.

First of all, create a directory over the path src/filter with the name of the new filter (e.g. src/filters/NewVCGAlgorithm) and put there all the source code files. As name for the filter class use the convention vcgXXXFilter (e.g. vcgNewVCGAlgorithmFilter) in order to distinguish it from the VTK classes.

Then there are two files to update to include the new filter inside the plugin:

CMakeLists.txt

Add the path of your directory filter inside the include_directories statement and add the path of the filter .cpp file in SERVER_MANAGER_SOURCES.

include_directories(
  vcglib
  ...
  src/filters/NewVCGAlgorithm
)

...

ADD_PARAVIEW_PLUGIN(
  VCG
  "1.0"
  SERVER_MANAGER_XML VCGPlugin.xml
  SERVER_MANAGER_SOURCES  ...
                          src/filters/NewVCGAlgorithm/vcgNewVCGAlgorithmFiler.cpp
)

VCGPlugin.xml

To make interactable your plugin from Paraview you have to add a SourceProxy tag which describe its componenents (e.g. input ports, output ports, parameters, etc). The body of the SourceProxy should be like as follow:

<SourceProxy name="NewVCGAlgorithmFilter"
             class="vcgNewVCGAlgorithmFilter"
             label="New VCG Algorithm">
  
  <!-- Put your stuff here -->
  
  <Hints> 
    <ShowInMenu category="VCG" />
  </Hints>
</SourceProxy>

Remember to declare the ShowInMenu tag with the category attribute set to VCG, so the filter will be grouped with the other ones in the VCG section of the Paraview Filters menu.

License

VCGLibForParaview is licensed under the terms of the MIT License. See the LICENSE file for details.