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    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
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      "source": [
        "%matplotlib inline"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "# PointCloud \n\nThis demo is a very short introduction to basic point clouds\nand a polygon mesh, that consists of two triangles, whose corner\npoints are given by some points of a cloud.\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "import numpy as np\nfrom itom import pointCloud\nfrom itom import polygonMesh\nfrom itom import point"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Create a new, empty ``pointCloud`` of type x,y,z only.\nPoint clouds can either be organized or unorganized. Organized point\nclouds have a height > 1, such that all points are organized in a 2d grid\nand the direct neighbours of every point are therefore defined.\nIn unorganized point clouds, the height is always <= 1 and the size is\nequal to the width of the cloud. No point has any neighbourhood relationship\nto other points. This is usually the default.\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "pcl = pointCloud(point.PointXYZ)\n\nprint(\n    \"Initial point cloud pcl, shape (h, w): %i x %i, fields: %s, organized: %i\"\n    % (pcl.height, pcl.width, str(pcl.fields), pcl.organized)\n)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add 8 points of a unit cube.\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "pcl.append(point(point.PointXYZ, (0, 0, 0)))\npcl.append(point(point.PointXYZ, (1, 0, 0)))\npcl.append(point(point.PointXYZ, (0, 1, 0)))\npcl.append(point(point.PointXYZ, (1, 1, 0)))\npcl.append(point(point.PointXYZ, (0, 0, 1)))\npcl.append(point(point.PointXYZ, (1, 0, 1)))\npcl.append(point(point.PointXYZ, (0, 1, 1)))\npcl.append(point(point.PointXYZ, (1, 1, 1)))\n\nprint(\n    \"Modified point cloud pcl, shape (h, w): %i x %i, fields: %s, organized: %i\"\n    % (pcl.height, pcl.width, str(pcl.fields), pcl.organized)\n)\n\nfor idx in range(pcl.size):\n    print(\"Point %i: %s\" % (idx + 1, str(pcl[idx])))\n\n# A polygon mesh can be constructed from a point cloud, that indicates\n# all corner points of the mesh and a table of vertices. Every entry in the\n# vertices table must contain 3 (default) or 4 values and indicate the indices\n# to the points in the cloud that define a triangle or quadrangle of the\n# mesh. If the normal vector to such a triangle points towards the outside\n# of the object, the order of the points is given by the right-hand rule, where\n# the thumbs shows in the direction of the normale vector.\n\n# create an array with two triangles. The first triangle has the corner\n# points with the indices 0, 1 and 2 of the cloud. The 2nd triangle consists\n# of the corner points 0, 1 and 3.\nvertices = np.array([[0, 1, 2], [0, 1, 3]])\n\n# create a mesh from the cloud and the vertices\nmesh = polygonMesh.fromCloudAndPolygons(pcl, vertices)\n\nprint(\"Mesh of %i polygons\" % mesh.nrOfPolygons)"
      ]
    }
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