3D Text Baseline in Ruby

[pc0158]

Is there a way to find the baseline of 3D text using Ruby, in the sense that the baseline is the line upon which most (but not all) letters appear to rest? In the string "MyText", for example, the default bounding box for the 3d text is the lower portion of the 'y' descender, which extends below the baseline. I'd like to locate an axis so it rests against the bottom of the "M", or whatever position is defined by the font's actual baseline.