v3.4 switched artwork width/height from normalised units
(longest edge = 1.00) to real centimetres (default longest edge =
120). This tool rescales an older building_v2.json in place
so it renders correctly in the 3.4 viewer. Everything runs locally in your browser.
1.00,
new files default to 120 cm. If your old file used a different
longest edge (e.g. you authored at 2.0 for a larger feel), divide
your intended cm by that and use the result.