  We report preliminary results from a study of the decay B0 --> D0bar pi+ pi-
using a data sample of 470.9 +/- 2.8 million BBbar events collected with the
BaBar detector at the Y(4S) resonance. Using the Dalitz-plot analysis
technique, we find contributions from the intermediate resonances D*_2(2460)-,
D*_0(2400)-, rho(770)0 and f_2(1270) as well as a pi+ pi- S-wave term, a D0bar
pi- nonresonant S-wave term and a virtual D*(2010)- amplitude. We measure the
branching fractions of the contributing decays.
