如何通过计算确定一个点是在 3D 模型内部还是外部 [英] How to determine whether a point is inside or outside a 3D model computationally

问题描述

我有一个 3D 模型的 .obj 和 .ply 文件.

I have a .obj and .ply file of a 3D model.

我想要做的是阅读这个 3D 模型文件，看看 3D 坐标列表是在 3D 模型空间内部还是外部.例如，如果 3D 模型是一个半径为 1 的球体，则 (0,0,0) 将位于内部 (True)，而 (2,0,0) 将位于外部 (False).当然我用的3D模型不是球体那么简单.

What I want to do is read this 3D model file and see if a list of 3D coordinates are either inside or outside the 3D model space. For example, if the 3D model is a sphere with radius 1, (0,0,0) would be inside (True) and (2,0,0) would be outside (False). Of course the 3D model I'm using is not as simple as a sphere.

我想添加一些我考虑使用的方法.因为我使用的是 Python，所以我想到了使用 PyMesh，因为它们的交叉特征看起来很有希望.然而，我拥有的坐标列表不是网格文件，而只是向量，所以它似乎不是合适的函数.

I would like to add some of the methods I considered using. Since I am using Python, I thought of using PyMesh, as their intersection feature looked promising. However the list of coordinates I have are not mesh files but just vectors, so it didn't seem to be the appropriate function to use.

我还发现了这个方法使用光线投射.但是，如何使用 PyMesh 或任何其他 Python 工具执行此操作是我需要建议的.

I also found this method using ray casting. However, how to do this with PyMesh, or any other Python tool is something I need advice on.

推荐答案

将我的评论转化为未来读者的答案.

Converting my comment into an answer for future readers.

您可以使用 Convex Hull 库来检查一个点是否在船体内.大多数库使用有符号距离函数来确定点是否在内部.trimesh 是实现此功能的库之一.

You can use a Convex Hull library to check whether a point is inside the hull. Most libraries use signed distance function to determine whether the point is inside. trimesh is one of the libraries that implements this feature.

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