SokDu
Pleat width calculation
Way of calculating the width of the third pleat of a twist. Blue triangle has to be twisted. Thick black lines are mountain folds which meet in twist center C. Paralell to them, thin black lines are walley folds of pleats which will extend from twist. The first two pleats are of the same width (here indicated wit a). Half of the angle between them (here is example of 135 degrees - that's 2φ, so φ is 67,5 degrees) is used in formula. Formula works theoretically from 0 to 180 degrees, altough in practice I estimate that useful range is roughly from 45 to 160 degrees.
As we know, at 120 degrees all three pleats are of the same width (as in triangular grid) and make classic triangle twist (with equiliteral triangle). If the angle between two equal pleats is less than 120 degrees, then pleat x is wider (x>a), if the angle is bigger, then, as here, plat x is narrower (x<a). Here a triangle is isosceles and meeting point of three pleats on the backside is at point C, mirrored across triangle's axis of symmetry.
Pleat width calculation
Way of calculating the width of the third pleat of a twist. Blue triangle has to be twisted. Thick black lines are mountain folds which meet in twist center C. Paralell to them, thin black lines are walley folds of pleats which will extend from twist. The first two pleats are of the same width (here indicated wit a). Half of the angle between them (here is example of 135 degrees - that's 2φ, so φ is 67,5 degrees) is used in formula. Formula works theoretically from 0 to 180 degrees, altough in practice I estimate that useful range is roughly from 45 to 160 degrees.
As we know, at 120 degrees all three pleats are of the same width (as in triangular grid) and make classic triangle twist (with equiliteral triangle). If the angle between two equal pleats is less than 120 degrees, then pleat x is wider (x>a), if the angle is bigger, then, as here, plat x is narrower (x<a). Here a triangle is isosceles and meeting point of three pleats on the backside is at point C, mirrored across triangle's axis of symmetry.