Quick Guide to Barycentric Coords

Quick Guide to Barycentric Coords.ipynb

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    "# Given we have performed NICP...\n",
    "src = TriMesh(...)\n",
    "tgt = TexturedTrimesh(...)  # in your case, as we are going to sample tcoords\n",
    "\n",
    "nicp_result = non_rigid_icp(src, tgt)"
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    "# rebuild a TriMesh from the result of the NICP using the from_vector machinery\n",
    "result = src.from_vector(nicp_result['deformed_source'].flatten())"
   ]
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    "# view this to see the result\n",
    "%matplotlib qt\n",
    "result.view()"
   ]
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    "# Now we want to describe where in the target mesh the deformed source\n",
    "# is sampled from at every vertex. As we sample in triangles, the natural\n",
    "# representation for this is a triangle index + barycentric coordinates for\n",
    "# each vertex in result. Handily, we have methods for this on TriMesh\n",
    "# in menpo3d.\n",
    "#\n",
    "# To use:\n",
    "\n",
    "bc, i = tgt.barycentric_coordinates_of_pointcloud(result)\n",
    "\n",
    "# These can then be used in \n",
    "#\n",
    "#    TriMesh.project_barycentric_coordinates(bcoords, tri_indices)\n",
    "#\n",
    "# in order to 'resample' a PointCloud from a corresponding mesh.\n",
    "#\n",
    "# To make this point clear, (bc, i) is a representation of a pointcloud\n",
    "# relative to a given triangulation. Between meshes that are *in correspondence*\n",
    "# (bc, i) allows us to transfer a pointcloud between the two.\n",
    "#\n",
    "# In your case, you want to sample from the texture coordinates on a textured trimesh.\n",
    "#\n",
    "# That might look something like this:\n",
    "\n",
    "# Build a 2D TriMesh for the tcoords.\n",
    "tcoords_trimesh = TriMesh(tgt.tcoords.points, tgt.trilist)\n",
    "\n",
    "# This trimmesh is in correspondence with tgt, so we can transfer our\n",
    "# relative pointcloud using the BC coords + tri indices\n",
    "\n",
    "sampled_tcoords_pointcloud = tcoords_trimesh.project_barycentric_coordinates(bc, i)\n",
    "\n",
    "print('The sampled tcoords are:')\n",
    "print(sampled_tcoords_pointcloud.points) "
   ]
  }
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