This section explains the calculations related to folding/unfolding operations.
When a bend is unfolded, the sheet metal deformation is represented by the
bend allowance V defined by the formula:
L = A + B + V

where:
L is the total unfolded length
A and B the dimensioning lengths as defined on the figures below:

Continued....
When you define the sheet metal parameters, a literal feature defines the
default K Factor, according to the DIN standard:
K = (0.65 + log(R / T) / 2) / 2
This formula can be deactivated or modified using Knowledge Advisor
workbench.
When a bend is created, the bend K Factor and the bend allowance literals
are created.
Two cases may then occur:
If the Sheet Metal K Factor has an activated formula and uses the
default bend radius as input parameter, the same formula is activated
on the bend K Factor with the bend radius as input.
Else the bend K Factor is a formula equal to the Sheet Metal K Factor.
The bend allowance literal is equal to a formula representing the use of the
bend K Factor. This formula is fairly complex and it is strongly recommended
not to delete it.
V = a * (R + k * T) – 2 * (R + T) * tan ( min(p/2,a) / 2)
Though it is possible to deactivate the formula to enter a fixed value.
Finally, the bend flat width is computed from the bend allowance value.