Applying an effect to export with alpha channel?


New to using HitFilm although I joined the forum a while back and watched a number of tutorials. This is a basic question but I couldn't find an answer in the forum posts.

I am trying to generate an effect, in this case Rain on Glass, so that I can export it with alpha to overlay on footage at a later date. So I am not looking to generate the effect on an image or video, but on a transparent "layer" and I don't seem to find a way to do that. It's fine when I try on an image or a video, but it does not seem to work with a grade layer or plane.

I think a workaround would be to use an image which is actually an entirely transparent PNG, but there must be a way to do this easily without the workaround: I just can't figure it out.

Sorry this is so basic: thank you for your pointers and suggestions.

Thank you.




  • Um. In this specific case, why? You could render the Rain on Glass on a 50% grey plane and composite the output using a Soft Light, Hard Light or Overlay Blend Mode, but the Rain on Glass filter also generates displacement on the source image for refractions. This is dependent on the source image and can not transfer to a new image. 

  • Ah, ok, that explains it. I will have to do it for each footage I want to try it on rather than use an overlay, then. Thanks a lot for your answer.

  • That answer was from memory. Double check the Rain on Glass effect. If it has a parameter that lightens or darkens the inside of the drops. If so, then I erred--you COULD export the effect over a grey plane and overlay it over other footage as discussed in the prior post. You could also add a Displacement effect to the image layer and select the Rain overlay as the Source Image/Displacement Map. This would give a refraction to (almost) match the actual effect. 

    But, then you're needing two layers, a blend mode and an effect to recreate something that can be done in Hitfilm with a single effect. Still seems odd to me. 

    However,  this would allow you to "export" a rain overlay that could work in any other NLE/photo editor  with blend modes and a Displacement effect that takes a map. So still has some good uses. 

  •  No, I can't see a parameter like that and I'll stick to doing it all in HitFilm.


    Thanks a lot.

  • You're welcome. Darn, I was hoping I'd overlooked something.

    Just for completeness here's an Ae tutorial on building rain on glass from scratch. These techniques work in Hitfilm--one would use Caustics instead of CC Glass and Heat Distortion (turn Diffusion to 0) instead of Turbulent Displacement--and can be adapted to most NLEs. Using the Hitfilm effect directly is still easier and faster, but pointing out other options.

    If you're in Pro there's another "roll your own" method using the particle sim. 

  • @JMcAllister yes. Helos when I remember to paste the damn link. 

  • Thank you both. I will have a look at at the AE tut and try to get a sense of how the Effect is done in HitFilm.

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