The new release with this feature is available . There are two modes that can be configure in the Material tab under Base color settings:
- Chroma key: allows to select a color that is treated as transparent with configurable deltas.
- Alpha in lower half: allows to upload videos where upper half is used for normal color data and lower half for opacity.
The first mode works well for things like fire effect with black background. It doesn’t work perfectly for green-screen videos. In our tests in such videos there often is some greenish color leaking at borders of opaque parts. We experimented with several algorithms, but none of them was fully able to remove the greenish color without also removing some areas of the tested videos that should be kept.
The second mode allows to fully control what should be removed and doesn’t have problems of the first mode. The drawback is that videos require additional work to prepare and are larger in size. See also this post for the description of this technique and format.