I'm animating the Alpha channel in slot colors within Spine to create a smooth glow fade-in/out effect, but the behavior becomes inconsistent after importing to Unreal Engine.
As shown in the gif, while the glow effect works properly in Spine by animating the Alpha value of the effect layer's slot, after importing to Unreal Engine the layer's Alpha values appear to only change abruptly (stepping between values rather than smooth interpolation), and the colors become solid.
Alpha value animation behaves inconsistently in Unreal Engine
The issue you're experiencing with alpha value animation in Unreal Engine is likely related to differences in color space and blending modes between Spine and Unreal Engine. In Spine, you might be using gamma space rendering, while Unreal Engine uses linear color space by default. This can cause discrepancies in how alpha values and colors are interpolated and displayed. To address this, you can try switching Unreal Engine's rendering pipeline to gamma space or previewing the blending in Spine 4.0-beta with linear blending to match Unreal Engine's settings. Additionally, ensure that your texture atlas is exported with the correct alpha settings, such as premultiplied alpha, to match Unreal Engine's expectations.
After changing the material's blend mode from Masked to Translucent, the initial issue was resolved, but normal map functionality was lost.