The parking lot at the San Fernando Valley Japanese American Community Center transforms every June — paper lanterns, taiko drums shaking the warm air, and three generations of families doing the same steps they've been doing here for decades. The SFV Obon Festival runs June 27 and 28 at 12953 Branford St in Pacoima: Saturday 4:30 to 10 PM, Sunday 4:30 to 9 PM. Admission is free. Obon is a Buddhist tradition for honoring ancestors, which means the atmosphere is simultaneously celebratory and reverent in a way that doesn't happen at other summer festivals. The bon odori circle dancing is open to everyone. You don't need to know the steps …