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achieving an EQ visualiser like drop off on a light wall made of independent elements

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Ethan Nixon
achieving an EQ visualiser like drop off on a light wall made of independent elements
on Jan 30, 2014 at 5:15:19 pm

hi, i'm fairly limited in my knowledge of expressions and have been ploughing my way through a "light wall" project i've received. the wall is made of 48 individual bulbs, with each bulb made up of a various layer effects laid over a solid, parented by a single slider in an adjustment layer.

i've created some nice tracer like effects with basic index based time delays by key framing a single bulb's adjustment layer and then referencing it with each sequential layer(i.e "thisComp.layer(index-5).effect("thresh")("Slider").valueAtTime(time-0.2)" where index-5 is the adjustment layer for the bulb directly below) but i've hit a brick wall trying to create an EQ like effect. presently, each bulb lights in sequence on the way up or down the light wall, but i'm trying to achieve an effect whereby the bulbs still sequentially trace, but each bulb stays lit until the one above it has dimmed - like an EQ.

i should clarify key-framed an animation for its luminescence to give it a nice organic feel, rather than a binary 100%/0% switch. this would be much easier to achieve with binary values, but it doesn't give the look i want.

sorry if this is confusing to read, i usually solve these kinds of problems on my own so i'm not used to communicating them.

if any of you could be so generous to help me out with this, i'll provide any additional info i can.

-ethan


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Walter Soyka
Re: achieving an EQ visualiser like drop off on a light wall made of independent elements
on Jan 30, 2014 at 8:31:39 pm

I'm having a hard time understanding what it is you want to accomplish. I get that you have simplified your rig to a single slider, but I don't understand what it is you want to accomplish in the end. Can you describe your end goal?

Also, I generally advise people to avoid "cascading" expressions such as these where each new layer is dependent on the calculation of expressions on every layer before it. Instead, I try to implement these as offsets, where every layer looks at the originally keyframed layer only and calculates its own time offset based on on index.

In other words, instead of setting them up like this:
  • Layer 1 is keyframed
  • Layer 2 looks at 1 at time x
  • Layer 3 looks at 2 at time y, which looks at 1 at time x
  • Layer 4 looks at 3 at time z, which looks at 2 at time y, which looks at 1 at time x


I set them like this:
  • Layer 1 is keyframed
  • Layer 2 looks at layer 1, at time x*(2-1)
  • Layer 3 looks at layer 1, at time x*(3-1)
  • Layer 4 looks at layer 1, at time x*(4-1)


Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Ethan Nixon
Re: achieving an EQ visualiser like drop off on a light wall made of independent elements
on Jan 31, 2014 at 6:07:31 am

thanks for your time, i really appreciate it!

firstly, re: cascading, i originally implemented the technique as a labour saving device and being able to apply a single copied expression to dozens of layers has certainly helped. i do appreciate its limitations though and it's probably a bad idea for best practices.

stripped down to its basics, i have a 4 x 12 wall. say, A - D (left to right), 1 - 12 (top to bottom)

i can easily create an effect where a light traces up from A12 to A1 at 0.2 second interval, so when A6 is at 100% brightness, A7 would be around 70%, A8 at 30% and A9 at 0% (with A5 also at 0%).

what i want to achieve is an EQ visualiser effect, whereby on the way up the wall A12 to A1 all remain lit after activating, creating a solid bar, only to deactivate in reverse order (A1 to A12) on the way back down (to mimic a falling EQ bar). in this instance, A12 would be the first light to turn on and the last to turn off.

it would be an extremely simple thing to do with a solid shape, but this is wracking my brain. i could introduce an "else" expression to every light's control layer specifying a time in which it should stop referencing the layer below and instead reference the layer above, but that seems extremely inelegant and labour intensive.

ideally, the solution would have some flexibility to it so i could create more varied EQ bouncing than a linear up and down motion.

again, thanks for your time. this isn't essential for my project(i've made do without it), but you know how it is when you hit a conundrum like this. it's an itch that must be scratched!

-ethan


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Walter Soyka
Re: achieving an EQ visualiser like drop off on a light wall made of independent elements
on Jan 31, 2014 at 2:37:46 pm

Ethan, thanks so much for explaining again. I understand much better now.

I think that there's a better approach to the rigging for animation here. Instead of animating A12 and linking the animation of every light to A12, create a new control for the column as a whole and link every light in the column to it.

See 7077_eqcolumnexpression.aep.zip for a simplified demonstration.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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