Hello,
I’m experiencing unexpected behavior when adjusting volume levels with blueprint fade functions set to use the sine based fade curves (S-Curve and Equal Power). The issue is most apparent when setting Volume Level to a value higher than 1.0, for example using the AdjustVolume function. What seem to be happening is that when the interpolation goes above 1, the volume starts decreasing instead of increasing, and then snaps to the target value when the fade time has elapsed.
Please see my attached image. The linear and logarithmic curves seem to work as expected, while the sine based ones are not.
In my test level (using vanilla UE 5.6.0), I’m playing a MetaSound sine tone controlled by a level blueprint graph. First I interpolate from volume 0. to 2. using the FadeIn node, then hold for 2 secs before going down to 0.25 using the AdjustVolume node. Then back again and finally fading out using the FadeOut node.
Steps to Reproduce
1) Play a looping sound on an audio component on default volume (1.0).
2) Adjust its volume level using the blueprint function AdjustVolume to 2.0 with “Sin (Equal Power)” as Fade Curve.
3) During playback, notice how the sound does not interpolate from the start value to the target value.
Hi Tobias, thank you for letting us know about this. We’re going to investigate and try to come up with a resolution for this behavior. Fundamentally, the problem here is that since Sine is a sinusoidal function, going outside the range [0,1] is going to cause the values to oscillate instead of continue up/down. Then once it’s done “fading” it just sets the value to the target you set with the fade function, causing the very abrupt jump. Ideally, the sine curve should scale up/down based on the target value.
Ok, thanks for looking into it!
Hey Tobias, we’ve added this bug to our task tracking. Thanks again for pointing this out to us!