Oh, sorry, I’m on Motion 4. I thought there was a behavior like it in Motion 3 but here is another way to do it: For a good example go to the Library tab, Content. Gadgets, Vacuum Tube. Notice how it’s glow comes in and out. That is because it has a Randomize Behavior set to the Bloom amount. It is set in the Randomize behavior in the Apply To section. You can set it to Opacity if you want.
Or another way and possible easier to do it is make the image fade with keyframes and then set the keyframes to continue forever. It is better described in my Creating a Hologram tutorial.
Best of luck.
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