Hi all, I am very new to YT and I have been trying to create a line plot for my GADGET-4 simulation output, but I keep running into a problem. I try to do a similar plot as that found here: https://yt-project.org/doc/cookbook/simple_plots.html#simple-1d-line-plottin.... I want to be able to 'draw' an arbitrary line and see how a quantity such as density changes along that line. My script and an example snapshot is linked below with the error I am getting following after. The code: http://paste.yt-project.org/show/392/ The snapshot and code: http://use.yt/upload/6dd0e0b8 YT version: 4.0.4 I keep getting this traceback error: " Traceback (most recent call last): File ~/PATH/yt_analysis.py:85 in <module> plot = yt.LinePlot(ds, "Density", (0.0, 0.0, 0.0), (0.0, 1.0, 0.0), 1000) File ~/.local/lib/python3.9/site-packages/yt/visualization/line_plot.py:174 in __init__ self._setup_plots() File ~/.local/lib/python3.9/site-packages/yt/visualization/line_plot.py:308 in _setup_plots x, y = self.ds.coordinates.pixelize_line( File ~/.local/lib/python3.9/site-packages/yt/geometry/coordinates/cartesian_coordinates.py:284 in pixelize_line arc_length, plot_values = _sample_ray(ray, npoints, field) File ~/.local/lib/python3.9/site-packages/yt/geometry/coordinates/cartesian_coordinates.py:47 in _sample_ray ray_coordinates = uvstack([ray[("index", d)] for d in "xyz"]).T File ~/.local/lib/python3.9/site-packages/yt/geometry/coordinates/cartesian_coordinates.py:47 in <listcomp> ray_coordinates = uvstack([ray[("index", d)] for d in "xyz"]).T File ~/.local/lib/python3.9/site-packages/yt/data_objects/data_containers.py:258 in __getitem__ self.get_data(f) File ~/.local/lib/python3.9/site-packages/yt/data_objects/selection_objects/data_selection_objects.py:211 in get_data self._generate_fields(fields_to_generate) File ~/.local/lib/python3.9/site-packages/yt/data_objects/selection_objects/data_selection_objects.py:232 in _generate_fields fd = self._generate_field(field) File ~/.local/lib/python3.9/site-packages/yt/data_objects/data_containers.py:299 in _generate_field tr = self._generate_fluid_field(field) File ~/.local/lib/python3.9/site-packages/yt/data_objects/data_containers.py:318 in _generate_fluid_field rv = finfo(gen_obj) File ~/.local/lib/python3.9/site-packages/yt/fields/derived_field.py:294 in __call__ dd = self._function(self, data) File ~/.local/lib/python3.9/site-packages/yt/geometry/coordinates/coordinate_handler.py:24 in _coords rv = data.ds.arr(data.fcoords[..., axi].copy(), units) File ~/.local/lib/python3.9/site-packages/yt/data_objects/selection_objects/data_selection_objects.py:418 in fcoords return self._current_chunk.fcoords File ~/.local/lib/python3.9/site-packages/yt/geometry/geometry_handler.py:255 in cached_func tr = self._accumulate_values(n[1:]) File ~/.local/lib/python3.9/site-packages/yt/geometry/geometry_handler.py:292 in _accumulate_values arrs.append(f(self.dobj)) File ~/.local/lib/python3.9/site-packages/yt/data_objects/index_subobjects/particle_container.py:17 in _func_non_indexed raise YTNonIndexedDataContainer(self) YTNonIndexedDataContainer: The data container () is an unindexed type. Operations such as ires, icoords, fcoords and fwidth will not work on it." Help with this would be highly appreciated. Kind regards, Christian