  Background: Several approaches are currently trying to understand the
generation of angular momentum in the fission fragments. The microscopic TDDFT
and statistical FREYA lead to different predictions concerning the opening
angle distribution formed between the two spins in particular at 0 and 180
degrees. Purpose: This letter aims to investigate how the geometry and the
quantum nature of spins impact the distribution of opening angles to understand
what leads to different model predictions. Method: Various assumptions of K
distribution (K=0, isotropic, isotropic with total K=0, and from TDFFT) are
investigated in a quantum approach. These distributions are then compared to
the classical limit using the Clebsch-Gordan coefficients in the limit of
$\hbar$ approaches zero. Results: It is shown that in all the schematic
scenario the quantal distribution of opening angle lead to the expected
behavior in the classical limit. The model shows that the quantal nature of the
spins prevents the population of opening angles close to 0 and 180 degrees. The
difference in opening angle in the 2D and isotropic 3D distribution is
discussed and it is shown that the realistic TDFFT opening angle distribution
presents an intermediate behavior between the two cases. Conclusions: The last
comparison reveals two key differences between the two models' predictions: the
quantal spins' nature in TDDFT and the assumption of zero K values in FREYA.
