Heya! Thanks for reaching out. Here is a screencap I just took of some settings in RPG Maker VX Ace for a tree I put together for the example tutorial that comes with the Train Station set. It currently plays the animation without a gap. The 'Graphic' in each event is taken from the '!TreeB_3.png' tilemap. The '!' in the name of the tilemap should be preventing any offset (from what I have read anyway, I am not super versed in RPG Maker VX Ace unfortunately). What does your 'Move Route' look like? Thanks for the love regarding my new interior pack!
