Hi, 
I'm trying to make a movie by depositing particles on to the mesh:

import yt

from yt.visualization.volume_rendering.api import MeshSource

from yt.units import Myr

import yt.visualization.eps_writer as eps

from yt.data_objects.particle_filters import add_particle_filter

import pylab as plt

plt.switch_backend('agg')


def star_filter(pfilter,data):

        age = data["all", "particle_age"]

        filter = age.in_units('Myr') > 0

        return filter

add_particle_filter("new_stars", function=star_filter, filtered_type="all", requires=["particle_age"])


ini=19

fin=21

CMAP = 'hot'

VMIN = 1e3

VMAX = 1e10


for x in range(ini, fin):

        filename="/lunarc/nobackup/users/samvad/FINAL-50-0.5/output/output_%0*d/info_%0*d.txt"  % (5,x,5,x)

        ds=yt.load(filename)

        time = ds.current_time

        ds.add_particle_filter("new_stars")

        ms =MeshSource(ds, ('deposit', 'new_stars_density'))

        sc.add_camera(ds)

        camera_position = ds.arr([0, 0, 0], 'code_length')

        cam.focus = ds.domain_center

        north_vector = ds.arr([0, 0, 0], 'dimensionless')

        cam.width = ds.arr([ 400400400], 'kpc')

        cam.resolution = (800, 800)

        cam.set_position(camera_position, north_vector)

        # actually make the image here

        im = ms.render(cam, cmap=CMAP, color_bounds=(VMIN, VMAX))

        plt.clf()

        fig = plt.gcf()

        ax = plt.gca()

        ax.imshow(im, interpolation='nearest', origin='lower')

        p = ax.imshow(ms.data, visible=False, cmap=CMAP, vmin=VMIN, vmax=VMAX)

        cb = fig.colorbar(p)

        cb.set_label(field_name[1])


        ax.text(25, 750, 'time = %.2e' % time, color='k')

       ax.axes.get_xaxis().set_visible(False) 
        plt.savefig('movie_frames/test_%.3d' % x)

But ending up with error:

Traceback (most recent call last):

  File "movie_new_stars.py", line 32, in <module>

    ms =MeshSource(ds, ('deposit', 'new_stars_density'))

  File "/home/samvad/yt-conda/lib/python3.6/site-packages/yt/visualization/volume_rendering/render_source.py", line 536, in __init__

    self.build_volume_embree()

  File "/home/samvad/yt-conda/lib/python3.6/site-packages/yt/visualization/volume_rendering/render_source.py", line 593, in build_volume_embree

    mesh_id = int(ftype[-1]) - 1

ValueError: invalid literal for int() with base 10: 't'

Any leads on this are highly appreciated.