Landscape Creation Beginner Question

mjbn77 · May 2, 2019, 1:08pm

I am about to start learning to make landscapes in Unreal Engine and I read several documentations and watched a couple of tutorials. But I am still struggling to fully understand that relation between and the differences between:

Section Size, Section Components, Number of Components, and Resolution

Why is section size determining performance and why is a smaller section size using more performance than a larger one?
Also, why would one choose section components 2x2 over 1x1?
What does resolution do? How does it affect my landscape? Higher resolution more details? What kind of details?

Lets say, I want to start with a landscape that is 500m x 500m in my game world. It is supposed to be beautiful and detailed, but should run good on current gaming hardware. What settings should I use for such a landscape?

Also, is it possible to change those settings after you created a landscape and worked on it for a while?

thank you!

northstar · May 2, 2019, 5:03pm

well, like anything… lets say you watch something on youtube at 360… its all blurry but runs really fast… you switch to 1080 and its really clear but runs really slow… its the same thing with landscape…

lets say you want to paint a path through some grass… if you have a low resolution you will literally ‘see’ the squares on the landscape… if you have a high resolution it will look smoother… its the same thing with shadows… the same thing with compiling…

and yes you can change things after you make a landscape… thats what i do… i make short movies so i want it small with lots of detail… i start with a 7x7 map with one section… then i go to Modes>Landscape>Manage… under landscape editor i choose ‘Change component size’… watch the resolution as you change the sizes… i pick ‘63x63’ with ‘2 sections’, then in ‘resize mode’ i choose ‘Resample’… below that you will see what you are starting from and what you are going to… click ‘apply’

it all depends on what you need and your computers power as to how you want to set it up…

mjbn77 · May 2, 2019, 6:25pm

northstar:

well, like anything… lets say you watch something on youtube at 360… its all blurry but runs really fast… you switch to 1080 and its really clear but runs really slow… its the same thing with landscape…

lets say you want to paint a path through some grass… if you have a low resolution you will literally ‘see’ the squares on the landscape… if you have a high resolution it will look smoother… its the same thing with shadows… the same thing with compiling…

and yes you can change things after you make a landscape… thats what i do… i make short movies so i want it small with lots of detail… i start with a 7x7 map with one section… then i go to Modes>Landscape>Manage… under landscape editor i choose ‘Change component size’… watch the resolution as you change the sizes… i pick ‘63x63’ with ‘2 sections’, then in ‘resize mode’ i choose ‘Resample’… below that you will see what you are starting from and what you are going to… click ‘apply’

it all depends on what you need and your computers power as to how you want to set it up…

Thank you for your answer. But I am still confused with section size and resolution. How does this all relate to actual Unreal Engine UU? I know that 1 UU is 1cm, but how does that relate to landscape resolution and section sizes choices?

northstar · May 2, 2019, 7:05pm

ahh… well there is a mathematical equation for sizes and sections which should be in the documentation, which i dont really use, so i never learned it…

https://docs.unrealengine.com/en-us/Engine/Landscape

i’m a visual type guy (smile) so i dont really know how everything works… like a neanderthal, i just turn on the light switch and go ‘ooooh ahhhh, its black magic!!!’ lol… best of luck, hope you find the answers you are looking for… wish i could have been of more help (smile)

anonymous_user_a9f52a15 · May 5, 2019, 10:47pm

Taken straight from Documentation here: https://docs.unrealengine.com/en-us/…TechnicalGuide

Unreal Documentation:

Components can optionally be divided into either 1 or 4 (2x2) subsections. These sections are the base unit of Landscape LOD calculation.

Using the 4 (2x2) subsections option gives you the same size heightmap as using four times as many components with only one subsection each, but using fewer components generally gives better performance.

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).

The choice of component size vs the total number of components is a performance trade-off. Smaller component sizes allow quicker LOD transitions and also allows for the occlusion of more terrain, but the smaller size necessitates more components.

Each component has a render-thread CPU processing cost and each section is a draw call, so try to keep these numbers to a minimum. For the largest Landscapes, Epic recommends a maximum of 1024 components.

This is a multi-faceted question. You can never attribute just one object to overall performance impact. Especially landscapes. You could make a 500mx500m landscape and have it run fine. But if you recklessly fill it without paying attention you could end up with a 500m squared lag fest.

Yes. I had to recently do this for my 4x4 tiled landscape. I changed component size from 1x1 to 2x2 which reduced my overall landscape components by an exponential factor.