Landscape/Map Height Limitations

So I have a sort of theoretical question. I have not personally found a “simple” way of going about it, but I’m curious if anyone else knows of one.

Let’s say you wanted to make a 1-1 recreation of Mount Everest for VR, and you wanted your player to start the climb from sea level. The peak of Everest is 8,848 meters, but something like World Machine has a limit of 2625 meters and a greyscale heightmap is necessarily limited to 255 points by it’s very nature. so how would you go about making a fully traversable mountain range or landscape that has an “unlimited” vertical height?

Would you try and stitch together landscapes and just change their Z-position in the world? And if so, how do you blend the edges so the nine adjacent tiles blend seamlessly with the physically higher tile?

Is there a way to use an RGB heightmap in Unreal? 16.7 million possible points would certainly cover it, you could stick Everest next to the Mariana Trench with barely a dent.

Would you make the landscape a static mesh? Isn’t that highly inconvenient? Is there some other application (Like Vue perhaps?) that makes texturing and rendering out large landscapes less awful?

I’m not actually trying to do anything like this at the moment, but the topic has crossed my mind dozens of times in the past. So does anyone have any thoughts on how to accomplish it?

If I’m not mistaken, Unreal’s heightmaps are actually 16bit grayscale, which means you get 65,535 points. That would work out to ~13.5 centimeters per level of gray. Of course if you really are going to make a to-scale level of that area, you’re likely not going to be starting any where near sea level, since the surrounding area is quite a few meters above sea level already. I mean, the entire Tibetan plateau itself is already at 1600m above sea level, so your Everest map won’t need to represent 8,848 meters of altitude difference, only 7248 meters.

The real issue will be the girth of the mountain. Most online references say that Everest has approximately a 10 mile radius at its base. That’s 20 miles from one side to the other. To represent that size accurately, assuming one pixel = 14cm , you would need to import a heightmap with a resolution of ~230,000 x 230,000. That would be quite difficult to do in the engine, even with World Composition. If you chunk that map up into 2k x 2k maps, you have to have somewhere north of 100 x 100 sub-levels. I’m having trouble landscaping and texturing and content filling a world that’s 8 x 8 sub-levels.

So, I made a landscape, dropped part of it to the floor, and another to the ceiling, then measured. It seems the vertical range limit on a single landscape is about 510 meters. Honestly that seems kind of low to me. If you go that distance all at once then yes, it seems like one hell of a jump, but if your making an open world game of some kind, then .5km in possible height, (assuming all of your landscape layers are zeroed out in Z), is not much to work with.

AFAIK the longest vertical drop on earth is ~[FONT=sans-serif]1,250m, so about 2½ x what landscape supports, and while something like that would make more sense as a mesh just from a detailing standpoint, if you were making a game level that climbed from “sea level” up into the mountain in a “seamless” fashion you’d smack into that 500m limit in short order.

[FONT=sans-serif]Again, I’m not actually “making” something like this, or asking how sane it would be in a gameplay environment. I’m well aware populating massive open worlds is a pain, but this still seems like something that should be doable.