# VisualizeStructuredGrid

vtk-examples/Cxx/StructuredGrid/VisualizeStructuredGrid

### Description¶

Visualize the points of a structured grid.

Question

### Code¶

VisualizeStructuredGrid.cxx

#include <vtkActor.h>
#include <vtkGlyph3DMapper.h>
#include <vtkMath.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkStructuredGrid.h>
#include <vtkStructuredGridGeometryFilter.h>
#include <vtkXMLStructuredGridWriter.h>

namespace {
/**
* Convert points to glyphs.
*
* @param points - The points to glyph
* @param scale - The scale, used to determine the size of the glyph
* representing the point, expressed as a fraction of the largest side of the
* bounding box surrounding the points. e.g. 0.05
*
* @return The actor.
*/
vtkSmartPointer<vtkActor> PointToGlyph(vtkPoints* points, double const& scale);

} // namespace
int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;

// Create a grid
vtkNew<vtkStructuredGrid> structuredGrid;

vtkNew<vtkPoints> points;
unsigned int numi = 2;
unsigned int numj = 3;
unsigned int numk = 2;

for (unsigned int k = 0; k < numk; k++)
{
for (unsigned int j = 0; j < numj; j++)
{
for (unsigned int i = 0; i < numi; i++)
{
points->InsertNextPoint(i, j, k);
}
}
}

// Specify the dimensions of the grid
structuredGrid->SetDimensions(numi, numj, numk);
structuredGrid->SetPoints(points);

std::cout << "There are " << structuredGrid->GetNumberOfPoints() << " points."
<< std::endl; // there should be 2*3*2 = 12 points
std::cout << "There are " << structuredGrid->GetNumberOfCells() << " cells."
<< std::endl; // The 12 points define the corners of 2 cubes/cells
// (4 points are shared by both cubes)

vtkNew<vtkStructuredGridGeometryFilter> geometryFilter;
geometryFilter->SetInputData(structuredGrid);
geometryFilter->Update();

// Create a mapper and actor
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(geometryFilter->GetOutputPort());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetPointSize(1);

// Visualize

// Map the points to spheres
auto sphereActor =
PointToGlyph(geometryFilter->GetOutput()->GetPoints(), 0.02);
sphereActor->GetProperty()->SetColor(colors->GetColor3d("Gold").GetData());

vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->SetWindowName("VisualizeStructuredGrid");

vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);

renderer->SetBackground(colors->GetColor3d("SteelBlue").GetData());

renderWindow->Render();
renderWindowInteractor->Start();

return EXIT_SUCCESS;
}

namespace {

vtkSmartPointer<vtkActor> PointToGlyph(vtkPoints* points, double const& scale)
{
auto bounds = points->GetBounds();
double maxLen = 0;
for (int i = 1; i < 3; ++i)
{
maxLen = std::max(bounds[i + 1] - bounds[i], maxLen);
}

vtkNew<vtkSphereSource> sphereSource;

vtkNew<vtkPolyData> pd;
pd->SetPoints(points);

vtkNew<vtkGlyph3DMapper> mapper;
mapper->SetInputData(pd);
mapper->SetSourceConnection(sphereSource->GetOutputPort());
mapper->ScalarVisibilityOff();
mapper->ScalingOff();

vtkNew<vtkActor> actor;
actor->SetMapper(mapper);

return actor;
}

} // namespace

### CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(VisualizeStructuredGrid)

find_package(VTK COMPONENTS
CommonColor
CommonCore
CommonDataModel
FiltersGeometry
IOXML
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)

if (NOT VTK_FOUND)
message(FATAL_ERROR "VisualizeStructuredGrid: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
target_link_libraries(VisualizeStructuredGrid PRIVATE ${VTK_LIBRARIES} ) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS VisualizeStructuredGrid MODULES${VTK_LIBRARIES}
)

cd VisualizeStructuredGrid/build

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./VisualizeStructuredGrid

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.