[Material] Glowing Alpha Plant Material

Hi folks,
Im trying to create a materiel wich acts normally in the light but starts glowing in the Shadows and darkness. Ive added a picture of a film woch inspiered me.

I managed to create a Material wich actually glows in one color and can use Opacitylayers for Grass and Leaves… thats all i managed to do.
I really could need some help here for i think this is impossible…

Here my progress:

I don’t think there’s going to be an easy way. I’d recommend a non-glow and glow version and hand place them so that it appears to be working w/o actually calculating light etc.

OR if its a day night thing then you can plug it into a blue print with material instances. But shadow not shadow is hard.

In the solus content examples (The Solus Project ~12 hours of UE4 in-depth tutorials + example content from Solus - Community Content, Tools and Tutorials - Unreal Engine Forums) there is shadow detection (Ray is cast from player to sun and if anything is hit then you are in shadow) but I don’t know how this would be applied to instanced grass. For a day/night behavior I would use a blueprint to update a material parameter which would be the alpha fpr a lerp between an emissive map and a vector 3 set to black.

sounds like a very nice idea… but in practice it would be very hard… you need a blueprint to detect if there is a shadow casting on it… then turn on the glow as needed… if you figure it out… let me know :slight_smile: