Hi, do you mind sharing some screenshots/videos of the problem? Or even .unitypackage with files included, so we could try on our side? Right now, it is a bit difficult to imagine what’s the exact issue.
Please bear with me, I have several more questions to understand you better. Could you tell me more how should it look like? What would be the expected result? Do you want the effect cover whole shape and do not fade out at the sides, or is it something else?