Toggle modifier On/Off for certain frames

-- create a global struct to hold all modifiers
-- and the frames on which these should be active
struct ModsOnOff
(
	public modifierObjects,
	public activeFrames,
 
	on create do
	(
		this.modifierObjects = #()
		this.activeFrames = #()
	)
)
global ModsOnOff = ModsOnOff()
 
-- create a callback that switches the modifiers
-- from the global struct on or off based on the frame number
-- beeing rendered or viewed in the viewport
fn modsOnOffCB =
(
	if not isStruct ModsOnOff then return()
 
	local cbParam = callbacks.notificationParam()
	local currentFrame = if cbParam == undefined then currentTime.frame else cbParam.frame
 
	for id = 1 to ::ModsOnOff.modifierObjects.count do
	(
		local modEnabled = findItem ::ModsOnOff.activeFrames (currentFrame as integer) != 0
		try ::ModsOnOff.modifierObjects[id].enabled = modEnabled catch continue
	)
)
-- add the callback for the renderer
callbacks.addScript #preRenderEval modsOnOffCB id:#modsOnOff
-- adding the callback to the viewports
registerTimeCallback modsOnOffCB
 
 
-- set the modifiers and frames...
-- after setting the values the state of the modifiers
-- will be correct when the time changes again
ModsOnOff.modifierObjects = #($Teapot001.modifiers[1], $Teapot002.modifiers[1])
ModsOnOff.activeFrames = #(2, 3, 6)
 
-- to remove the callbacks, run the follwoing two lines:
-- callbacks.removeScripts id:#modsOnOff
-- unRegisterTimeCallback modsOnOffCB