UE4 for Large Scale Scenes.

Hello Guys !

First of all i would like to thank everyone for this great community, i have found tons of helpful information reading through the posts here.
i work in the architectural visualization field, and have been learning and researching UE4 to use if for architectural visualization for about a year now.
i have formulated so far a decent foundation to start from. from scene preparation to packaging. i will gladly be sharing my personal workflow, with an example to my work so far
as well as a list of resources that i have found most beneficial and the things that sped up my learning curve, as well as my actual workflow. with some mistakes that have made, problems
that i have faced, and how i went around those. it’s a really nice software, and i am constantly learning something new every single time.

i would like to ask from the experienced members to help point me out in the right direction, i would like to know how to proceed on working on big scale projects in unreal, ( as i know that a workflow for larger scenes would be Different than smaller ones in terms of geometry, and assets.).

it would be really nice to point out a few tips on how to handle bigger arch viz projects , as i haven’t tested working on any yet, i would like to listen to other people’s experiences and comments regarding working on large scale architectural scenes.

the aim is to be able to create a large area of retails, within a building with an open roof structure, where plenty of natural sun light can come in.

if anyone have worked on large area please let me know how would you advise proceeding in such a workflow.
in terms of lighting , map sizes, software limitations, models, light mass issues that i might encounter, or any other issues, and if there are any ways to prevent this from happening, and working in an efficient and clean way.

your feedback is much appreciated, although the use of UE4 in architectural visualizations is relatively new to the market ( and new to us ), but i sense a bright future, and we as arch viz artist are pushing to bring this to the market, so i would really appreciate your help , and feedback for our mutual benefit :stuck_out_tongue:

Cheers !

I’m looking for the same thing, as I would like to create a city in UE4, I have the layout of the streets modeled in 3d already as well as the cad files, but when looking at tutorials online for UE4, they usually use splines for roads as it gives you the road markings and everything, but it’s not as exact as drawing it in 3d and importing as a static mesh, another issue is the size of that mesh is quite large, as a result the quality of the curves is very bad, what’s your suggestions for creating an exact city as i have in CAD, knowing that it has lots of curves as well as varying road sizes.

Any help from experienced UE4 users will be much much appreciated!

Here are a few tips:

Start with dividing your project in logical smaller sub areas. Decide where you want more detail or what will be just background architecture.

  • use less detail in background areas.
  • the bigger your scene the more optimized it needs to be. Not just for performance but also for light map size or texture caching.

This brings us to the next problem: Lighting.

  • you need to decide if you want to have baked or dynamic lighting. Baked lighting is better looking and more efficient to render but depending on how optimized your assets are you might end up with unmanageable light map sizes. So if you didn’t really optimize all your assets then you may need to go to fully dynamic lighting.
  • set your skybox / lighting / further away environment early because it affects the lighting in your scene and how every object will look at the end.

Use sub-levels for each area.

  • areas with more detail need additional sub levels for this detail. This isn’t really a technical requirement but you might want to stream these small items in and out if needed. The best optimization is removing an object from the scene if it isn’t visible.

Optimization tips

  • as a general advice: unreal always liked smaller objects over huge assets. Not just for light map sizes but also for collision and general handling. If you have 2 symmetrical building parts than mirror them in unreal and not in 3ds max.
  • but​​​​​ watch out for your draw calls. An object with 10 material id’s has 10 draw calls. With Arch Viz objects you can quickly have too many draw calls. Recommended are something like 1000-1500 draw calls in view. If you have 100 cars with 10 materials on each of them then that’s almost all the draw calls you can have. (In Arch Viz you can probably go a bit higher with the draw calls as there is no game play happening that eats up your CPU performance. Draw calls happen on the CPU not GPU.)
  • use cull distance volumes that automatically remove invisible objects according to their size.
  • use foliage for vegetation. But remember: whatever that foliage is painted on needs to stay with this base mesh in the same level or you won’t be able to modify it later on.
  • use instancing as much as possible. Light poles, benches, windows, anything that is repeated will render a lot faster when instanced. It pays off a lot if these objects are optimized. You get away with a few high poly houses but you won’t get away with 100 super expensive car meshes.
  • don’t forget collision if you want to move around in the scene. Often per poly collision is fine for ArchViz. You can set that in your player character for the entire scene.

Other than that it is just a matter of scale. You can have one house where you put a thousand little things in or you can have a small city with a thousand larger items. It will render the same speed if the detail is properly scaled up or down. You can even have both if you only render the small items when you actually see them.