The dice and the board (top right) both contribute to the "strength".
Since we haven't explained how they contribute, let me try to unravel the formula:
(after dice roll)
1. sum dice faces
2. advance the board (top right) by dice sum
3. use modifier from board (if exists) and add or subtract from dice sum
4. divide [sum #3] by 6 (to prevent physics jitter and OOB)
5. check if [sum #4] is less than 1, if so adjust sum to be 1 (it's no fun to be stuck)
TL;DR: max([dice sum +/- board modifier] / 6, 1)