为什么多面体会单独渲染，但与完整的模型结合在一起

Question

下面的代码试图使一个简单的3D三角形在较大型号的侧面支持时工作。

它自己运行良好，但是当我将其添加到更大的模型中时，三角形的一个侧面没有呈现，我会收到的警告" UI-Warning：对象可能不是有效的2-manifold，可能需要维修！"

使其甚至是陌生人，当我单击"保存"时，该模型被重新绘制，并且模型显示为缺失的侧面。

我正在使用openscad v.2019.05

我正在解决问题，并在它们周围制作一些小物体和船体((。但是，我希望此代码可以工作。

//For some odd reason, this module works well on its own.
//It does does not render correctly when used as part of a larger model.
//Then it will miss a side.
//It shows correctly up when saving though. 
module supportTriangle(height=10, length=10, thickness=10){
    trianglePoints = [
    [ 0, 0, 0 ],
    [ thickness, 0, 0 ],
    [ 0, 0, height ],
    [ thickness, 0, height],
    [ 0, length, 0],
    [ thickness, length, 0]];
    triangleFaces = [
    [ 0, 1, 5, 4 ],
    [ 0, 1, 3, 2 ],
    [ 2, 3, 5, 4 ], 
    [ 0, 4, 2 ],
    [ 1, 3, 5 ]];
    polyhedron(trianglePoints, triangleFaces);
}

我会收到" UI-warning：对象可能不是有效的2个manifold，可能需要维修！"当渲染与较大模型

Answer 1

尝试以下：

module supportTriangle(height=10, length=10, thickness=10){
    trianglePoints = [
    [ 0, 0, 0 ],
    [ thickness, 0, 0 ],
    [ 0, 0, height ],
    [ thickness, 0, height],
    [ 0, length, 0],
    [ thickness, length, 0]];
    triangleFaces = [
    [ 0, 1, 5, 4 ], 
    [ 2,3,1,0], // i reversed these to keep them clockwise 
    [ 4,5,3,2 ], // i reversed these to keep them clockwise 
    [ 0, 4, 2 ],
    [ 1, 3, 5 ]];
    polyhedron(trianglePoints, triangleFaces);
}
supportTriangle(10,10,10);
cube(5,center=true); // just an extra thing to make it error if order is wrong

请参阅：https://en.wikibooks.org/wiki/openscad_user_manual/primive_solids#polyhedron所有面都必须在相同方向上排序点。OpenSCAD更喜欢顺时针从外部向外看每个脸时。从背面，底部从底部观看，等等。