Ios 使用SCNShape和UIBezierPath绘制圆弧

我试图使用以下代码在

SCNShape

中绘制一块饼：

UIBezierPath *piePiece = [UIBezierPath bezierPath];
[piePiece addArcWithCenter: CGPointZero radius:  0.150 startAngle: 0.0 endAngle: M_PI/6  clockwise: YES];
[piePiece closePath];
SCNShape *pieShape = [SCNShape shapeWithPath: piePiece extrusionDepth: 0];
pieShape.firstMaterial.diffuse.contents = [UIColor blueColor];
pieShape.firstMaterial.doubleSided = YES;
SCNNode *pieNode = [SCNNode nodeWithGeometry: pieShape];

但我得到以下形状：

我看不到弧线。我做错了什么

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谢谢

您必须将UIBezierPath的平面度更改为较低的值。迅速：

pieShape.flatness = 0.0003