Just to simplify the calculation a bit… If CG Dealers' calculation is correct (and to my eyes, looks like it mostly is), there's a bit that actually cancels out, and some inaccuracy caused by Gaea's UI.
So:
Unreal Engine X/Y scale: 100 * [Desired resolution in meters] / [heightmap resolution]
Unreal Engine Z scale: 100 * [Gaea Scale
] / 512
To explain:
CG Dealers' full calculation for X/Y makes sense. Note that Real scale
would be usable for the X/Y scale, if Gaea didn't calculate it based on its "Standard" (powers of 2) resolution, rather than the UE resolution selected - and also chops off probably a few too many decimals for it to be usable. E.g. a map with Terrain Definition Scale
set to 4000 and exported as 4033 will show 4000/4096 ≅ .977px/m rather than 4000/4033 ≅ .992px/m. So, you're better off doing that calculation yourself - like CG Dealers does.
As for the Z scale, CG Dealers' full calculation is:
([Gaea Height
] / [max height in meters] ) multiplied by
([max height in meters] / [Gaea Height-Scale Ratio
]) multiplied by
100 * (1 / 512)
1/512 is straight from Unreal Engine's documentation. And 100 is due to UE's standard unit being centimeters. Note that CG Dealers divides by his "max height in meters" only to multiply by it in the next part of the calculation. The two cancel out.
The Height-Scale Ratio
in Gaea, which CG Dealers uses, is calculated simply by dividing the Terrain Definition Height
by Scale
- and then, again, chopping off probably a few too many decimals. So, like Real scale
, better to just do that calculation yourself too - height divided by scale. But making that change shows us that we're actually multiplying by Height
and dividing by Height
- the two cancel out. Leaving us with 100 * [Gaea Scale
] / 512.
This, of course, assuming that the rounded Real scale
and Height-Scale Ratio
aren't also the ones Gaea uses to save the files. 😉