Randomly choose a mesh upon spawning foliage type?

[Sitrec]

@NisshokuZK;378929

I have some experience manipulating the foliage placed with the foliage tool at run-time. I can tell you that if all else fails, you can do a trick at BeginPlay where you read all foliage instance data, remove those instances and reinsert the instance info in another instanced static mesh component.

Foliage placed by the foliage tool is stored as, not surprisingly, instanced static mesh components. All those ISMs are kept in a InstancedFoliageActor. So if you find the InstancedFoliageActor at run-time using an TActorIterator, you can read each foliage instance’s transform. You could reuse those transforms as instances in different ISMs, for example randomly select one of your three types. Then remove them from the original foliage ISM et voila. Hope that helps.

Thank you! We have been thinking of doing something similar to this but was so sure it would be too demanding to do it in runtime since we have hundreds upon hundreds of thousands of meshes. But we might be wrong, we never ended up trying. Do you think it would be viable for processing that many meshes? I’ts closer to a million.

@Antidamage;379175

Have you thought about using a shader to produce your different variations? I’m not sure if you could do much based on proximity to specific objects, but there are definitely proximity functions in materials. At the absolute worst you could use their position to vary the way they look and have that function repeat over short distances, appearing pseudo-random.

If you look at how SpeedTree materials work, you’ll see they do some trickery with the vertex shader and some texture maps to animate in the wind. You could come up with a coefficient based on location and modify the overall size and then tint/lerp the textures you want to use. That at least connects the colour and texture of the foliage to the size behaviour, which the current foliage implementation won’t give you.

You shouldn’t need to compensate anyone for this, it’s very straight forward! Have a crack at it and let me know how you go!

Thank you! I did use this for our grass before the new grass tools were released. I had a list of different grass textures that it would randomly choose based on a per-instance random and also different sets for different parts of our map based on a low resolution mask that masked out the different areas. I don’t use that now but still use random color variation for most of my foliage. It definitely helps with breaking things up but I wish i could use my different meshes in an easy way.