PDA

View Full Version : Stopping a repeated non-motion channel after a certain time?



Spinland
09-19-2015, 02:03 PM
I'm doing a sequence where a police car arrives on the scene with lights flashing. I'm using point lights with intensity and lens flare intensity keyed for a 1 second cycle which then repeats for a couple of minutes. Before the car drives off I want to shut down the lights but I haven't figured out how I can stop the repeat post behavior on cmmand. From searching it seems Motion Mixer would be useful but that tool doesn't seem to be able to load the non-motion channels like intensity.

Can anyone suggest a better way?

Many thanks in advance!

ernpchan
09-19-2015, 02:27 PM
Quick and dirty way would be to bake out the channel and delete the keys you don't need.

Maybe you can expression link the intensity envelope to an null that in turn you fade between a static null and a cycling null. Not sure if the values you need will translate all the way through though.

Spinland
09-19-2015, 06:47 PM
Thanks, I think baking out the channels is a great approach. I'll let you know how it works out.

jeric_synergy
09-19-2015, 08:06 PM
If you're talking the light bar lights, which are inside something else, you could have a 'flag' object (in gaffer-talk), that goes opaque when you want the light to turn off. They're still there, of course, but you can't see them.

Realistically, very few shots are MINUTES long, so baking out keys is a perfectly reasonable approach. RR is the king of key-baking, so check his material about ways of doing it.

What you really want is something equivalent to AE's loopOut() expression, or actually loopIn(), which does exactly what you want. --There's probably some Expression that wouldn't be too hard to develop, that would watch a "dimmer" value (a null's position) and suppress the channel when the dimmer moved to, say, zero. Well, gee, really just a multiplier, no?

EDIT: geez, I really gotta start reading more closely: the above para is what ernpchan said. Senility!

Spinland
09-20-2015, 09:57 AM
Heh. Thanks! Yeah, the actual on-screen time is only a hair over one minute so baking was certainly the way to go. Worked a treat.

I should probably know this but I'm coming up blank as to who RR is. Can you advise?

Thanks again!

ernpchan
09-20-2015, 11:03 AM
I think he's referring to Ryan Roye (aka chazriker) .

jeric_synergy
09-20-2015, 11:32 AM
I think he's referring to Ryan Roye (aka chazriker) .
Forsooth.

JoePoe
09-20-2015, 03:29 PM
I know you've got it solved with baking.
Just adding to the conversation :).


Quick and dirty way would be to bake out the channel and delete the keys you don't need.

Maybe you can expression link the intensity envelope to an null that in turn you fade between a static null and a cycling null. Not sure if the values you need will translate all the way through though.

Just need one null.... and the expression is already done..... as the Cycler Modifier :hey:.

Below: the full cycle of the light pattern is controlled by a 90 (or whatever you want) turn on the Null's heading.
You can see in the graph editor the dashed line starting at frame 50 where to pattern has been suppressed.

129829

Edit: hmmm, trying to stack a couple Cyclers (pattern > time off > pattern again).... doesn't seem to work.

MonroePoteet
09-21-2015, 10:20 AM
If it's a simple sine wave, you could also use the Oscillator modifier in the Graph Editor=>Modifiers tab and specify the End Frame to your needs. Note that although the cycle time in Oscillator is specified in seconds, it seems to think there are 24fps regardless of the scene settings, so if you want a 1.0 second flash, you have to use 1.25 for the seconds value in Oscillator.

mTp