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Local Globals

Posted: Fri Jan 06, 2017 3:17 pm
by Sadler
What about this idea...

Globals that are only local to a particular scene but which are exposed in the Scene module when that scene is included within another. This would allow a parent scene to pass values into the child scene.

I think it would also be neater to have globals local to the scene for those variables that only pertain to the scene rather than the whole comp. It would give a sense of encapsulation to scenes with private and public parameters.

As an example of where this might be useful is when you include the same scene more than once but you want to change aspects of each differently (e.g. colour). Also, in the case where you have say, 20 globals in a scene for a very specific purpose these would not pollute global panel and mental real-estate for every other scene.

Re: Local Globals

Posted: Fri Jan 06, 2017 4:53 pm
by Magic
Yeah, it's a pretty good idea. I think someone posted about it before but I can't seem to find it...

Mental real-estate is quite valuable :).

Re: Local Globals

Posted: Sun Sep 03, 2017 2:28 pm
by Terry Payman
This is exactly what I need.
I remember seeing this topic but had only recalled the headline concept of local/scene parameters from my first reading.

On review, I now realise that Sadler's post elegantly summarises one of the requirements that emerged from the challenges of a recent project - for the exact use case that Sadler gave as an example.

I wish to encapsulate all my most frequently used video processing effects within "SceneInput" scenes, to facilitate re-use and maintenance, but I need the ability to pass different parameters to individual instances.

Further thoughts
I see benefit in a distinction between Scene parameters and Scene locals. Only the parameters would be exposed at the higher module level (with their defaults defined at scene level).

Perhaps this could be implemented by having a globals/locals panel, with an "Add local" button as well as "Add global". A right-click option on a local's selection tab could then be "Expose as Module parameter" or some such wording.

I can't see how a link button would be meaningful for a parameter's default value. Perhaps the link symbol could change to a "P" to signify that a local has been exposed as a parameter.

Case study
For a band music performance at a large international show, I was providing Magic-processed live camera visuals to be luma-keyed over pre-programmed video backgrounds for display on LED video screens. All was locked to MIDI Timecode, along with the pre-programmed light show.

During the afternoon rehersals for the evening show, the director asked me to provide processed camera visuals for all 14 songs of the performance, rather than the 3 originally requested which I had pre-programmed.

The last-minute changes meant for each additional song I needed to vary the colour of various elements of the Magic output to match the accompanying colour schemes of the background video and the.stage light show

The additions proved too great a challenge and were only partly completed by the time of the show. The band were delighted with the overall result, but it could have been so much better.

I now realise that a design approach with colour/hue/saturation as fundamental parameters would have greatly facilitated the process, and will be very useful in future.

Photo
Magic-processed live video on sides and behind stage performance (Expo 2017, Astana). The stage and screens were huge - you can just see the performers. Three separate Magic systems were run in parallel, fed from three different video cameras, giving the director a choice of three different live video sources to key over the pre-recorded background video. A feed from the TV coverage gave a fourth option.

Re: Local Globals

Posted: Tue Sep 05, 2017 3:26 pm
by Magic
Yep I've actually been thinking about something similar. Lots of work to be done.

Great photo btw. Got any video?

Re: Local Globals

Posted: Wed Feb 07, 2018 12:45 am
by mcornholio
Hey! So, what about "Locals" and scene parameters? This feature would be super cool!

Re: Local Globals

Posted: Mon May 03, 2021 12:09 pm
by WoodlandSpirit
I know I made another post about this already (great minds and all) but just wanted to voice support for the local globals idea here as well, a new user and already ran into some scenarios where this would be useful.

Thank you!