Hey all,
I have something a little different this week, slightly less game related but still fun I hope.
I wanted to cover the concept of creating a chromakey material for a kind of green screen removal effect on images or videos. In this tutorial, we cover how to play a video inside of the engine so that we can move on to adding our own custom material to the video next time.
Hey, thanks for posting those two videos, they were really helpful. I do have a question however, have you been able to replicate this in 4.18 at all? The first video worked a charm, however in the second video I’m having issues. I followed your steps about 3 times to ensure that I hadn’t missed anything and I’m using the same footage that you used, however my video is either opaque or fully transparent. I think I’ve narrowed it down to the ‘Edge Offset’ parameter (governed by the AlphaOffset node) as whenever the value is below 1 the issue occurs. Go above 1 and the video pops back into existence.
Any suggestions?
I should note that I’m running UE4 on Mac OS High Sierra.
Any help would be greatly appreciated, thanks again for making those videos in the first place.
All the best,
Miley
UPDATE: Just repeated the exact same steps in 4.15 and it worked with zero issues so it must be something to do with 4.18. Could it be a simple setting or console command of some sort? Thanks again for demonstrating this, its really helpful, I just hope I won’t have to roll back to 4.15 and start my project over!
Got it working in 4.18.3! Just add an absolute value (Abs) node after the first Subtract node. Subtracting the texture sample and the green color can end up with negative values, so if you take the absolute value of that before plugging it into the Power node, it should work out. The Power node can end up taking the square root of a negative which makes it freak out. I also got solid results with ColorGain 2, Edge Offset 0.85, Emissive 0.65, and Power 0.61.