VTK切割图 - 技术栈

vtkPlane：表示一个无限的平面，要由一个法向量和一个通过该平面的点来定义

SetOrigin：设置原点（平面经过的点）
SetNormal：垂直于平面的方向向量（法向量）

vtkCutter：使用指定的vtkPlane对数据进行切割

SetCutFunction：切割工具，可以是vtkPlane
SetInputData：切割的数据
Update：执行切割

cpp 复制代码

 // 获取数据集的边界框
double bounds[6];
m_dataSet->GetBounds(bounds);

// 根据方向和位置计算切割平面
// model.sliceDirection: 0=XY平面(Z值变化), 1=XZ平面(Y值变化), 2=YZ平面(X值变化)
// model.slicePosition: 0.0~1.0 相对范围
double origin[3] = {
    0.5 * (bounds[0] + bounds[1]),
    0.5 * (bounds[2] + bounds[3]),
    0.5 * (bounds[4] + bounds[5])
};
double normal[3] = {0.0, 0.0, 1.0};

const double t = qBound(0.0, model.slicePosition, 1.0);
switch (model.sliceDirection) {
    case 0: // XY: Z = zMin + t * (zMax - zMin)
        origin[2] = bounds[4] + t * (bounds[5] - bounds[4]);
        normal[0] = 0.0; normal[1] = 0.0; normal[2] = 1.0;
        break;
    case 1: // XZ: Y = yMin + t * (yMax - yMin)
        origin[1] = bounds[2] + t * (bounds[3] - bounds[2]);
        normal[0] = 0.0; normal[1] = 1.0; normal[2] = 0.0;
        break;
    case 2: // YZ: X = xMin + t * (xMax - xMin)
        origin[0] = bounds[0] + t * (bounds[1] - bounds[0]);
        normal[0] = 1.0; normal[1] = 0.0; normal[2] = 0.0;
        break;
    default:
        return false;
}

// 构建切割管线：DataSet -> Plane + Cutter -> Mapper -> Actor
m_slicePlane = vtkSmartPointer<vtkPlane>::New();
m_slicePlane->SetOrigin(origin);
m_slicePlane->SetNormal(normal);

m_sliceCutter = vtkSmartPointer<vtkCutter>::New();
m_sliceCutter->SetCutFunction(m_slicePlane);
m_sliceCutter->SetInputData(m_dataSet);
m_sliceCutter->Update();

if (m_sliceCutter->GetOutput()->GetNumberOfCells() == 0)
    return false;

m_sliceMapper = vtkSmartPointer<vtkDataSetMapper>::New();
m_sliceMapper->SetInputConnection(m_sliceCutter->GetOutputPort());
m_sliceMapper->ScalarVisibilityOff();

if (!m_sliceActor) {
    m_sliceActor = vtkSmartPointer<vtkActor>::New();
}

m_renderer->RemoveActor(m_sliceActor);
m_renderer->AddActor(m_sliceActor);
m_sliceActor->SetMapper(m_sliceMapper);
m_sliceActor->GetProperty()->SetRepresentationToSurface();
m_sliceActor->GetProperty()->SetColor(1.0, 0.2, 0.2);
m_sliceActor->GetProperty()->SetLineWidth(2.0);
m_sliceActor->GetProperty()->LightingOff();

// 切割显示时隐藏本体，避免截面被不透明外表面完全遮挡。
if (m_actor)
    m_actor->SetVisibility(0);

// 切割显示时隐藏云图色标，避免右侧图例误导。
if (m_scalarBar)
    m_scalarBar->SetVisibility(0);