Not on idea but a feedback (or even warning :))
As non uniformly scaled terrain (landscape) seem to be supported in UE, they're actually not at least when generated with Datasmith 🙂 I incidentally discovered that in a project where I thought a rectangular (with a 2/1 ratio and kind of power of 2 dimensions (well in Epic sense of it (4033...) would save me some space and gave me more res, but in fact yet with Datasmith it's possible to give some different scales for x,y,z and that it appear so once generated in Ue editor, under the hood, collision mip surface is still done as if the landscape had some uniform x,y scales:
say you import a DS terrain where in the end it gives you a landscape with scale x : 300, scale y 200 and scale z 20, although it's displayed correctly once spawned and you can check scales are set correctly (300,200,20), it will be impossible to spawn procedural foliage on it without discrepancies (floating over terrain, buried under etc) , (yet grass types are generated correctly, go figure) or even try to snap some actors onto terrain surface, as apparently all calculations are done over a ghostly terrain scale of 300,300,20, and not 300,200,20. Took me some time to realize that "bug"...
So beware, do not import non square terrain with DS in UE...
