kongkong
So, Can export PNG directly like Photoshop?
No, unfortunately, if you export an image which is set to additive blend mode with transparent background in the PNG format, the result will look different from the output from Photoshop.
However, since you are going to use the output PNG in After Effects, then I think it would be somewhat usable if you output it with a pure black background.
For example, after exporting the following image from Spine:
If the background of the composition is black, you can simply place the effect image in Additive blend mode; otherwise, duplicate the image, set the blend mode of the upper image to "Stencil Luma" to make the background of the effect transparent, and composite the resulting composition in Additive to use the black background area transparent. The effect composited on top of Spineboy's gun in the following image is the one using "Stencil Luma":
Although the color will be different, you may want to use the "Luminescent Premul" blend mode to remove the black haze.
In any case, the result will not be the same as Photoshop, and I think you may already know this way, but I just wanted to let you know just in case.
