Add text to Tachyon image?

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Hi folks, is there a way to add text to Tachyon images? I tried

S = sphere(opacity=0.8, aspect_ratio=[1,1,1])
T = text3d('hello world', (2,2,2))
M = S + T
M.show(viewer='tachyon', frame=False)

in the Sage notebook, but that didn't work. Got a sphere but no text. I also searched the docs, but couldn't find anything relevant.