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Animating randomized visibility

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Greetings all,
I'm posting this question on more than one thread as I have a situation that's not quite a newby-question, though hoping to get some advice or guidance on something specific that I imagine may require an Expresso setup, though perhaps it’s possible to achieve by other means. 

What I’d like to do is animate the visibility (alpha value, but not the Transparency property) of a group of 50 or so discreet geometry objects  so that they go from fully invisible to fully visible one by one.
  • Each object should fade from 0 to 100% opacity over the course of about 6 frames, though randomizing slightly this per object would be optimal (some could take 4 frames, some could take 8 frames, etc.)
  • I’d want to make the fade-on time of each object based on its y-position value, so that objects at the bottom of the pile appear first and objects at the top appear last
  • The total animation will need to be about 4 seconds, so at 0:00, none of the objects are visible, but at 4:00 all objects are visible
  • The objects are already placed and I don’t have much flexibility to change this
  • The 50 objects don’t all have the same material. There are 3 discreet materials applied across the 50 objects (but none of the objects has more than a single material applied to it.)

The brut-force way to do this would obviously be to set up more materials than I already have, apply them to the appropriate objects  and manually animate the Alpha property of each material. Kinda trying to avoid this, since object count is fairly high.

I imagine this could be approached something like the following  ( though don’t have much experience  with Expresso or other scripting to know if this is a wise approach).
  • Get the points of an Array object or MoGraph Cloner to conform to coordinates of the pre-placed set of geo objects
  • Use some animatable property of the Cloner to drive the visibility or alpha property of each object.

Any advice here would be massively appreciated!


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You only need to post once ! I have removed the other 2...



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There's probably a way to program this, but with only 50 objects, brute force might be easiest:


The display tag has a visibility option that you can animate from 0-100%. If you want a uniform animation, a new object will start its animation every other frame (50 objects over 4 seconds at 24fps). You can drop a display tag on your first object, animate 0-100% visibility over frames 0-6, copy the tag onto object 2, then shift the keyframes on the new tag 2 frames later. Repeat until finished. 


If you've got your objects in order in your object manager, this will be really quick and easy. If not, you could start at the top and animate backwards so that the objects you've already keyframed will end up at 0% and disappear from the viewport, making it easy to select new objects as you work down your pile of objects.

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  • Hi DeCarlo


    Many thanks for your response. I was able to solve my problem using a MoGraph solution, on the advice from another forum (thanks Luke Letellier - if you happen to be on this forum.)


    By simply parenting all of my geo objects under a MoGraph Fracture, I'm able to treat the array of objects as I would the clones in a MoGraph Cloner. 


    After the parenting, I apply a Color Shader to the Alpha property of each material, and then apply an animated Plain Effector to the Fracture which takes care of turning on the alpha opacity for each object as the Plain Effector moves along.


    In addition to the Plain Effector, I apply a Random Weight Effector to the Fracture and this takes care of randomizing the total effect.



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    Perfect.  I figured you could do this with MoGraph, but I wan't familiar enough with the effectors to know what combination would have achieved the desired animation.  

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