Landscape memory size on disk - questions

[MysteryBlues]

Ernesto, thanks for taking the time.

you should try using some LOD on the Terrain but of course

I sure plan to use landscape pieces with lower resolution (much lower) for the distant vistas, for the ones the player won’t walk over. But for the ones he’ll actually explore, it unfortunately needs to look nice and display a standard resolution. One that won’t feel noticeable.
If you’re talking about using some kind of dynamic LOD for the landscape components, the landscape actor in UE4 already takes care of that, of swapping different LODs on demand based on the camera frustum / viewport. It even takes care of dynamically changing tessellation based on distance from camera, surface normal angle etc. Probably you know that.

You mean as in like by just putting that Terrain alone the level became large in size?

Yeah, only added the terrain. The other stuff I added is only going to add to the GPU cost (volumetric fog, skylight etc). I deleted some small stuff in the level here after reading your reply, to check it better. It went from 433.558 to 432.958 Mb on disk. Only thing I left there, aside from the landscape actor, was what comes with the “default” new map: sun directional light, player start, floor (a cube static mesh) and skysphere.

I’m curious exactly how much is the triangle count on the terrain?

The 8129 x 8129 pixels heightmap (PNG, 16-bit) has 8129 x 8129 vertices, according to the “landscape recommended sizes” on the docs.
So, if 4 verts make for a face, and a face equals 2 triangles…
But each component’s section doesn’t share vertices with neighbor sections, so the math gets a bit more complex.

From the docs:

The size of each section (in number of vertices) must be a power of two (with a maximum of 256x256). This is so that the different LOD levels can be stored in mipmaps of the texture. This will lead to the number of quads in a component either being a power of two minus 1 (if 1 section per component) or a power of two minus 2 (if 4 sections per component).

An individual component is illustrated below (outlined in green) containing four sections. Each section is made up of 9 (3x3) quads. Again, you can see that the vertices where the sections meet are duplicated.