vtkToolbox for MATLAB

Overview

vtkToolbox is a MEX interface to the VTK library. It provides functions to read and write VTK files and to apply VTK filters to VTK datasets. Currently, two types of datasets are supported: vtkPolyData and vtkUnstructuredGrid (both represented as vtkPointSet). The toolbox is based on two functions for converting a vtkPointSet into a MATLAB struct and vice versa: vtkToStruct() and structToVtk().

Format of the MATLAB struct

The following format is used to represent a VTK dataset as a MATLAB struct:

myStruct.points:    [numPoints x numDim double/single/(u)intN], numDim <= 3
myStruct.cells:     [numCells x maxNumPointsPerCell int32]
myStruct.cellTypes: [numCells x 1 uint8] (see https://vtk.org/doc/nightly/html/vtkCellType_8h_source.html)
myStruct.pointData: [1 x 1 struct of point data arrays] (optional)
myStruct.cellData:  [1 x 1 struct of cell data arrays]  (optional)
myStruct.fieldData: [1 x 1 struct of field data arrays] (optional)

File input/output

The functions vtkRead() and vtkWrite() can be used to read and write various types of files supported by the VTK library.

Filters

The general procedure used by filters in the toolbox is:

• A MATLAB struct is passed to the MEX function and converted into a vtkPointSet using structToVtk().
• Desired VTK filters are applied to the vtkPointSet.
• The vtkPointSet is converted back to a MATLAB struct using vtkToStruct() and returned by the MEX function.

Building the MEX functions

Before you can use the toolbox, you first have to compile the MEX functions for your platform:

• Install VTK (either using a package manager or from source – see https://vtk.org/Wiki/VTK/Configure_and_Build)
• Compile the MEX functions using CMake. In the folder "vtkToolbox", run:

  mkdir build
  cd build
  cmake ..
  make
  

Adding new functions

The functionality of the toolbox can easily be extended by creating and compiling new functions:

• Duplicate the folder vtkTEMPLATE and replace "TEMPLATE" in file names and the cxx file.

• Adapt the cxx file by parsing the needed inputs and adding the desired operation(s) or filter(s) to the section "Apply operations to pointSet".

• Rerun CMake after adjusting "CMakeLists.txt" as follows:

  • Add a new line with all C++ source files of your MEX function to the section "Build MEX functions".
  • You might have to add more VTK components under the section "Set up VTK dependency".

• Duplicate MATLAB/vtkTEMPLATE.m and adapt it accordingly. This script is only needed for providing a function help and a function hint.

License

All source code is subject to the terms of the Mozilla Public License, v. 2.0.
Copyright 2020 Steffen Schuler, Karlsruhe Institute of Technology.

Contact

Steffen Schuler
Institute of Biomedical Engineering
Karlsruhe Institute of Technology
www.ibt.kit.edu