paperLamp simulation Question

hi all

I would like simulation Chinese paper lamp by using kangaroo, and in the end I would like use SLA 3D print to print it out, the goal is achieving folding structure with 3DP. in the beginning the simulation looks great(see figure 1). However, I find some question(see figure 2), the red wire frame on the right should be symmetry like the physical lamp, but it has a extend distance now.

I should like to keep the wire frame structure with same length after simulation.

maybe I miss some setting in Kangaroo, can any one fix it?  thanks in advance.

I put this ghx file under the attach.