“圓柱”曲面展開

“圓柱”曲面展開

沿軸向展開，展開後橫座標爲弧長，縱座標爲軸向座標，高程爲曲面到參考圓柱曲面的距離。

定義參考圓柱

//！軸
enum AXIS {
	AXIS_X,
	AXIS_Y,
	AXIS_Z
};
//! 投影圓柱
struct GEO_CYLINDER
{
	//!軸向
	AXIS Axial;
	//!徑向：橫/縱 ，橫向弧長，縱向偏差
	AXIS RadialTran;
	AXIS RadialLong;
	//!徑向截面圓心中心
	double CenterTran;
	double CenterLong;
	//!半徑
	double R;  
};

由“圓柱”曲面展開“平”曲面

void  CylinderToPlane(vtkPolyData* srcData, vtkPolyData* destData, GEO_CYLINDER proj_cylinder) {

	vtkSmartPointer<vtkPoints>srcPoints = srcData->GetPoints();
	//destData->DeepCopy(srcData);
	vtkSmartPointer<vtkPoints>destPoints = vtkSmartPointer<vtkPoints>::New();
	int num = srcPoints->GetNumberOfPoints();
	double p[3],r[3],cross[3];
	//v1展開起點，v0 當前截面的圓
	double v0[3] = { 0 }, v1[3] = {0};
	//截面中心點
	v0[proj_cylinder.RadialTran] = proj_cylinder.CenterTran;
	v0[proj_cylinder.RadialLong] = proj_cylinder.CenterLong;
	//沿軸向展開
	v1[proj_cylinder.RadialTran] = proj_cylinder.R;
	v1[proj_cylinder.RadialLong] = 0;
	 
	//弧長
	double azmith;
	for (int i = 0; i < num; ++i) {

		srcPoints->GetPoint(i, p);
		v0[proj_cylinder.Axial]= p[proj_cylinder.Axial];
		vtkMath::Subtract(p,  v0, p);
		azmith = vtkMath::AngleBetweenVectors(v1,p);
		vtkMath::Cross(v1, p, cross);
		if (cross[proj_cylinder.Axial]<0)
			azmith = vtkMath::Pi()*2-azmith;

		r[proj_cylinder.RadialTran]= proj_cylinder.CenterTran+ azmith*proj_cylinder.R;
		r[proj_cylinder.Axial] = v0[proj_cylinder.Axial];
		r[proj_cylinder.RadialLong] =sqrt(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]) - proj_cylinder.R;

		//CyPointToPPoint(p, r, proj_cylinder);
		destPoints->InsertPoint(i,r);
	}
	//添加切口線上的點（恢復時使其閉合）

	/*double bound[6];
	srcData->GetBounds(bound);
	p[proj_cylinder.RadialTran] = proj_cylinder.CenterTran + 2*vtkMath::Pi()*proj_cylinder.R;
	p[proj_cylinder.Axial] = bound[2* proj_cylinder.Axial];
	p[proj_cylinder.RadialLong] = 0;
	destPoints->InsertNextPoint(p);
	p[proj_cylinder.Axial] = bound[2 * proj_cylinder.Axial+1];
	destPoints->InsertNextPoint(p);*/

	//
	destData->SetPoints(destPoints);
}

由“平”曲面恢復“圓柱”曲面

void PPointToCyPoint(double pp[3], double cy[3], GEO_CYLINDER proj_cylinder)
{
	double arc_length;
	//弧長
	arc_length = pp[proj_cylinder.RadialTran] - proj_cylinder.CenterTran;
	//徑向-橫向
	cy[proj_cylinder.RadialLong] = proj_cylinder.CenterLong + sin(2*vtkMath::Pi()-arc_length / proj_cylinder.R)*(proj_cylinder.R+pp[proj_cylinder.RadialLong]);
	//軸向
	cy[proj_cylinder.Axial] = pp[proj_cylinder.Axial];
	//徑向-縱向
	cy[proj_cylinder.RadialTran] = proj_cylinder.CenterTran + cos(2 * vtkMath::Pi()-arc_length / proj_cylinder.R)*(proj_cylinder.R + pp[proj_cylinder.RadialLong]);
}

void PlaneToCylinder(vtkPolyData * srcData, vtkPolyData * destData, GEO_CYLINDER proj_cylinder)
{
	vtkSmartPointer<vtkPoints>srcPoints = srcData->GetPoints();
	destData->DeepCopy(srcData);
	vtkSmartPointer<vtkPoints>destPoints = vtkSmartPointer<vtkPoints>::New();
	int num = srcPoints->GetNumberOfPoints();
	double p[3],r[3];
	for (int i = 0; i < num; ++i) {
		srcPoints->GetPoint(i, p);
		PPointToCyPoint(p,r,proj_cylinder);
		destPoints->InsertPoint(i, r);
	}
	destData->SetPoints(destPoints);
}

計算參考圓柱

	vtkPolyData * destData = reader->GetOutput();
	double bound[6];
	destData->GetBounds(bound);
	//定義轉換圓柱
	GEO_CYLINDER proj_cylinder;
	proj_cylinder.R = (bound[1] - bound[0]) / 2;             //半徑  
	proj_cylinder.Axial = AXIS::AXIS_Y;  //沿Y軸展開
	proj_cylinder.RadialTran = AXIS::AXIS_X;
	proj_cylinder.RadialLong = AXIS::AXIS_Z;
	proj_cylinder.CenterTran = (bound[1] + bound[0]) / 2.0;
	proj_cylinder.CenterLong = (bound[5] + bound[4]) / 2.0;

”圓柱“曲面
計算參考圓柱

”圓柱“曲面展開

圓柱“曲面展開和參考圓柱展開

測試

int main(int argc, char const *argv[])
{
	double radius = 1;
	double center[3] = {0,0,0};

	vtkSmartPointer<vtkCylinderSource> cylinderSource = vtkSmartPointer<vtkCylinderSource>::New();
	cylinderSource->SetCapping(false);
	cylinderSource->SetRadius(radius);
	cylinderSource->SetCenter(center);
	cylinderSource->SetHeight(5);
	cylinderSource->SetResolution(100);
	cylinderSource->Update();

	//定義參考圓柱
	GEO_CYLINDER proj_cylinder;
	proj_cylinder.R = radius;             //半徑  
	proj_cylinder.Axial = AXIS::AXIS_Y;  //沿Y軸展開
	proj_cylinder.RadialTran = AXIS::AXIS_X;
	proj_cylinder.RadialLong = AXIS::AXIS_Z;
	proj_cylinder.CenterTran = center[AXIS::AXIS_X]; //橫向
	proj_cylinder.CenterLong = center[AXIS::AXIS_Z]; //縱向
	//
	vtkSmartPointer<vtkPolyData>destPlane = vtkSmartPointer<vtkPolyData>::New();
	CylinderToPlane(cylinderSource->GetOutput(), destPlane, proj_cylinder);
	//
	vtkSmartPointer<vtkDelaunay2D>delaunay2d = vtkSmartPointer<vtkDelaunay2D>::New();
	delaunay2d->SetInputData(destPlane);
	delaunay2d->Update();

	vtkSmartPointer<vtkPolyData>cylinderBack = vtkSmartPointer<vtkPolyData>::New();
	PlaneToCylinder(delaunay2d->GetOutput(), cylinderBack, proj_cylinder);
	//source
	vtkSmartPointer<vtkPolyDataMapper> polyDataMapperSource =
		vtkSmartPointer<vtkPolyDataMapper>::New();
	polyDataMapperSource->SetInputData(cylinderSource->GetOutput());
	vtkSmartPointer<vtkActor> actorSource = vtkSmartPointer<vtkActor>::New();
	actorSource->SetMapper(polyDataMapperSource);
	vtkSmartPointer<vtkRenderer> rendererSource = vtkSmartPointer<vtkRenderer>::New();
	rendererSource->SetViewport(0, 0, 0.2, 1);
	rendererSource->AddActor(actorSource);
	rendererSource->SetBackground(10, 0, 0);

	//plane
	vtkSmartPointer<vtkPolyDataMapper> polyDataMapperDest =
		vtkSmartPointer<vtkPolyDataMapper>::New();
	polyDataMapperDest->SetInputData(delaunay2d->GetOutput());

	vtkSmartPointer<vtkActor> actorDest = vtkSmartPointer<vtkActor>::New();
	actorDest->SetMapper(polyDataMapperDest);
	actorDest->GetProperty()->SetColor(0, 0, 1);

	vtkSmartPointer<vtkRenderer> rendererDest = vtkSmartPointer<vtkRenderer>::New();
	rendererDest->SetViewport(0.2, 0, 0.8, 1);
	rendererDest->AddActor(actorDest);
	rendererDest->AddActor(actorSource);

	rendererDest->SetBackground(10, 0, 0);

	//backToCylinder
	vtkSmartPointer<vtkPolyDataMapper> polyDataMapperBack =
		vtkSmartPointer<vtkPolyDataMapper>::New();
	polyDataMapperBack->SetInputData(cylinderBack);

	vtkSmartPointer<vtkActor> actorBack = vtkSmartPointer<vtkActor>::New();
	actorBack->SetMapper(polyDataMapperBack);
	actorBack->GetProperty()->SetColor(0, 0, 1);

	vtkSmartPointer<vtkRenderer> rendererBack = vtkSmartPointer<vtkRenderer>::New();
	rendererBack->SetViewport(0.8, 0, 1, 1);
	rendererBack->AddActor(actorBack);
	rendererBack->SetBackground(10, 0, 0);

	vtkSmartPointer<vtkRenderWindow> renderWin = vtkSmartPointer<vtkRenderWindow>::New();
	renderWin->AddRenderer(rendererSource);
	renderWin->AddRenderer(rendererDest);
	renderWin->AddRenderer(rendererBack);

	renderWin->SetSize(1500, 600);

	vtkSmartPointer<vtkRenderWindowInteractor>rwi =vtkSmartPointer<vtkRenderWindowInteractor>::New();
	rwi->SetRenderWindow(renderWin);
	rwi->Initialize();
	rwi->Start();
	return 0;
}

展開到復原