VTK中導入並顯示STL、3DS文件

　　VTK（visualization toolkit）是一個開源的免費軟件系統，主要用於三維計算機圖形學、圖像處理和科學計算可視化。VTK是在三維函數庫OpenGL 的基礎上采用面向對象的設計方法發展起來的，它將我們在可視化開發過程中會經常遇到的細節屏蔽起來，並將一些常用的算法封裝起來。它包含一個C++類庫，和解釋封裝層，包括Tcl/Tk、Java、Python等。 采用這種架構的優勢是我們能使用C++語言建立高效的算法，用其他的腳本語言（如TCL、Python）可以進行快速的開發。

　　VTK中可以導入/導出或讀/寫多種三維格式的文件，可以參考What 3D file formats can VTK import and export? The following table identifies the file formats that VTK can read and write. Importer and Exporter classes move full scene information into or out of VTK. Reader and Writer classes move just geometry.

File Format	Read	Write
3D Studio	vtk3DSImporter
AVS "UCD" format	vtkAVSucdReader
Movie BYU	vtkBYUReader	vtkBYUWriter
Renderman		vtkRIBExporter
Open Inventor 2.0		vtkIVExporter/vtkIVWriter
CAD STL	vtkSTLReader	vtkSTLWriter
Fluent GAMBIT ASCII	vtkGAMBITReader
Unigraphics Facet Files	vtkUGFacetReader
Marching Cubes	vtkMCubesReader	vtkMCubesWriter
Wavefront OBJ		vtkOBJExporter
VRML 2.0		vtkVRMLExporter
VTK Structured Grid †	vtkStructuredGridReader	vtkStructuredWriter
VTK Poly Data †	vtkPolyDataReader	vtkPolyDataWriter
PLOT3D	vtkPLOT3DReader
CGM		vtkCGMWriter
OBJ	vtkOBJReader
Particle	vtkParticleReader
PDB	vtkPDBReader
PLY	vtkPLYReader	vtkPLYWriter
Gaussian	vtkGaussianCubeReader
Facet	vtkFacetReader	vtkFacetWriter
XYZ	vtkXYZMolReader
Ensight ‡	vtkGenericEnSightReader

　　STL格式是一種3D模型文件格式，它采用三角形離散地近似表示三維模型，目前已被工業界認為是快速成形領域的標准描述文件格式。這種文件不包括模型的材質等信息。下面的代碼將讀入一個STL文件將其顯示在窗口中，並可以用鼠標和鍵盤進行一些簡單的交互。

#!/usr/bin/env python
 
import vtk
 
filename = "myfile.stl"
 
reader = vtk.vtkSTLReader()
reader.SetFileName(filename)
 
mapper = vtk.vtkPolyDataMapper()

mapper.SetInputConnection(reader.GetOutputPort())
 
actor = vtk.vtkActor()
actor.SetMapper(mapper)
 
# Create a rendering window and renderer
ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
 
# Create a renderwindowinteractor
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
 
# Assign actor to the renderer
ren.AddActor(actor)
 
# Enable user interface interactor
iren.Initialize()
renWin.Render()
iren.Start()

 C++版代碼如下：

#include <vtkPolyData.h>
#include <vtkSTLReader.h>
#include <vtkSmartPointer.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>

int main ( int argc, char *argv[] )
{
    if ( argc != 2 )
    {
        cout << "Required parameters: Filename" << endl;
        return EXIT_FAILURE;
    }

    std::string inputFilename = argv[1];

    vtkSmartPointer<vtkSTLReader> reader =
        vtkSmartPointer<vtkSTLReader>::New();
    reader->SetFileName(inputFilename.c_str());
    reader->Update();

    // Visualize
    vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(reader->GetOutputPort());

    vtkSmartPointer<vtkActor> actor =
        vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);

    vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
    vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
    renderWindow->AddRenderer(renderer);
    vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
    renderWindowInteractor->SetRenderWindow(renderWindow);

    renderer->AddActor(actor);
    renderer->SetBackground(.3, .6, .3); // Background color green

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

    return EXIT_SUCCESS;
}

---

　　3ds文件是是Autodesk 3dsMax使用的一種二進制存儲格式，VTK中可以使用vtk3DSImporter類導入3ds文件。

　　vtkImporter is an abstract class that specifies the protocol for importing actors, cameras, lights and properties into a vtkRenderWindow. The following takes place: 1) Create a RenderWindow and Renderer if none is provided. 2) Call ImportBegin, if ImportBegin returns False, return 3) Call ReadData, which calls: a) Import the Actors b) Import the cameras c) Import the lights d) Import the Properties 7) Call ImportEnd

　　Subclasses optionally implement the ImportActors, ImportCameras, ImportLights and ImportProperties or ReadData methods. An ImportBegin and ImportEnd can optionally be provided to perform Importer-specific initialization and termination. The Read method initiates the import process. If a RenderWindow is provided, its Renderer will contained the imported objects. If the RenderWindow has no Renderer, one is created. If no RenderWindow is provided, both a RenderWindow and Renderer will be created. Both the RenderWindow and Renderer can be accessed using Get methods.

#!/usr/bin/env python

# This example demonstrates the use of vtk3DSImporter.
# vtk3DSImporter is used to load 3D Studio files.  Unlike writers,
# importers can load scenes (data as well as lights, cameras, actors
# etc.). Importers will either generate an instance of vtkRenderWindow
# and/or vtkRenderer or will use the ones you specify.

import vtk

# Create the importer and read a file
importer = vtk.vtk3DSImporter()
importer.ComputeNormalsOn()
importer.SetFileName("myfile.3ds")
importer.Read()

# Here we let the importer create a renderer and a render window for
# us. We could have also create and assigned those ourselves like so:
# renWin = vtk.vtkRenderWindow()
# importer.SetRenderWindow(renWin)

# Assign an interactor.
# We have to ask the importer for it's render window.
renWin = importer.GetRenderWindow()
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

# Set the render window's size
renWin.SetSize(500, 500)

# Set some properties on the renderer.
# We have to ask the importer for it's renderer.
ren = importer.GetRenderer()
ren.SetBackground(0.1, 0.2, 0.4)

iren.Initialize()
renWin.Render()
iren.Start()

 

參考：

VTK/Examples/Python/STLReader

vtk3DSImporter Class Reference

常見三維文件格式之STL, VRML, X3D

3D模型文件--STL,OBJ,3DS

讀取3ds文件

Example demonstrates the use of vtk3DSImporter

http://public.kitware.com/pipermail/vtkusers/2011-June/068231.html

http://www.vtk.org/gitweb?p=VTK.git;a=blob;f=Examples/Rendering/Python/CADPart.py