1.VTK默认透视投影（近大远小）；

1.调用vtkCamera的ParallelProjectionOn函数开启

2.通过vtkCamera的SetParallelScale缩放

3.通过vtkCamera的SetClippingRange设置前后裁剪平面

2.正交投影（平行投影，远近一样）：

//开启正交投影模式

renderer->GetActiveCamera()->ParallelProjectionOn();
renderer->GetActiveCamera()->SetParallelScale(10);
renderer->GetActiveCamera()->SetClippingRange(-100, 100);

正交投影样例：

Code:

#pragma once
//#include "vtk_include.h"#include <vtkLODActor.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>#include <vtkRenderer.h>#include <vtkSphereSource.h>
#include <vtkTextActor.h>#include <algorithm>#include <array>
#include <vtkPlaneSource.h>
#include<stdio.h>
#include<iostream>
using namespace std;void main(){vtkNew<vtkNamedColors> colors;vtkNew<vtkRenderer> renderer;//平面vtkNew<vtkPlaneSource> plane;plane->SetCenter(0, 0, 0);//设置平面中心点坐标plane->SetOrigin(-10, -10, 0);//设置平面起点坐标，一般为平面左下角plane->SetPoint1(10, -10, 0);//设置平面第一条轴的长度plane->SetPoint2(-10, 10, 0);//设置平面第二条轴的长度plane->SetNormal(0, 0, 1);//设置平面的法向量plane->SetXResolution(10);//x方向分割数plane->SetYResolution(10);//y方向分割数vtkNew<vtkPolyDataMapper> planeMapper;planeMapper->SetInputConnection(plane->GetOutputPort());vtkNew<vtkActor> planeActor;planeActor->SetMapper(planeMapper);planeActor->GetProperty()->EdgeVisibilityOn(); //显示线框renderer->AddActor(planeActor);//球vtkNew<vtkSphereSource> sphereSource;sphereSource->SetRadius(5);sphereSource->SetCenter(5, 0, 0);sphereSource->Update();vtkNew<vtkPolyDataMapper> sphereMapper;sphereMapper->SetInputConnection(sphereSource->GetOutputPort());vtkNew<vtkActor> sphereActor;sphereActor->SetMapper(sphereMapper);sphereActor->GetProperty()->SetColor(colors->GetColor4d("Green").GetData());sphereActor->GetProperty()->EdgeVisibilityOn(); //显示线框renderer->AddActor(sphereActor);renderer->ResetCamera();//开启正交投影模式renderer->GetActiveCamera()->ParallelProjectionOn();renderer->GetActiveCamera()->SetParallelScale(10);renderer->GetActiveCamera()->SetClippingRange(-1000, 1000);renderer->SetBackground(colors->GetColor3d("SteelBlue").GetData());vtkNew<vtkRenderWindow> renderWindow;renderWindow->AddRenderer(renderer);renderWindow->SetWindowName("RenderWindowNoUIFile");vtkNew<vtkRenderWindowInteractor> iren;iren->SetRenderWindow(renderWindow);renderWindow->Render();iren->Initialize();iren->Start();}