Image models don't understand it either, they only know the typical "look" of something but not the correct proportions or number of parts. If you have the word "wheel" in the prompt they might turn every circle-like shape in the image into a car wheel because it cannot selectively apply parts of the prompt to parts of the image.

At least the few models I tinkered with all had this issue, and without some additional guidance that understands scene composition and anatomy/proportions in three dimensions this probably won't fundamentally improve.

I got it to extrude a cylinder into a sinusoidal, guiding it by feeding it back screenshots of the scene converted to ascii.