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This LARGE Room -- Workflow Tips?

Hey Everyone.

I’m trying to model this big room in Blender, and bring it into Unreal.
I was wondering if someone might drop me a few words to get started on the following questions:

  • Should I make a single polygon for the roof? Should I close it off with thicker geometry?

  • any idea why these lights look so yellow (on the in-engine) screen?

  • any general workflow tips on common problems people new to Arch-Viz make?

Much thanks.

There are plenty of tutorials in the unreal website, There you’ll find typical workflows that will get you started.
Element could be Either planes or solid objects. The unwrapping part can make a difference regarding lighting.
I usually work fro a model given from an Architect so everything is a solid object.

hey @fco3d thanks for the reply. t.

The unwrapping tip affecting lighting is a good one – can you be more specific? Do you mean the way you mark your seams?

When they give you ‘solid’ objects, do you mean the roof geo is attached to the wall geo?

Yes, the unwrapping should be clean enough, placing closer polygons closer to each other instead of further apart as some auto unwraps do.
Steam roller for 3D Max does a good job but in some geometries some manual rearrangement is necessary.
Data smith also works pretty well. Just be sure to uncheck compress light maps under World settings. and also adjust the lightmap size as need it, 1024 is OK for more cases but the larger your geometry the more resolution you may need.

I usually start from Models from REVIT, Sketchup or Rhino so everything is a 6 faces polygon, some SketchUp wall are single planes, in that case, I try to increase the light resolution map and increase the precision of the light mass to avoid light leaks, if that still happens then I cover that area with other geometry.

Francisco,
Thanks very much taking the tip to go over those tips, I really appreciate your reply – the only one!

Although I’m working in Blender, I’m working in an academic context, so I’ll look into Max and Steam roller. Same for Data smith.

The ‘uncompressed light maps’ is a super valuable tip.

You’re the man!

No problems, I am also a new user for Unreal I just share what I have learned here and there.

This forum is not much interactive for some reason, some thread are fast-moving others barely alive not sure why.

I thought you were using 3D Max, but Blender should do about the same, I Use Cinema 4D and Modo tool so it applies for any other 3D software.
Take a read to these docs, there is a lot of good info in here.

best luck.

When you have separate meshes that are joined together then make sure all verts are exactly in the same spot so the engine can weld them or you get light leaks and other problems. For example your walls are 2 pieces but your ceiling is only one. Divide the polygon of the ceiling and snap the middle verts to the wall verts. Make sure your lightmap resolution is large enough for your pieces.

Personally I would make one mesh for ceiling and walls inside together and give it a lightmap res of 2048. Then make another mesh encapsulating the inner mesh so you don’t have light bleeding. Give it at least 30cm wall thickness. The more the better. The outer mesh can have a low res because you never see it.

Thanks very much @S-Dot – super appreciate the tips

Hey Guys, can I trouble you with another rookie question:

As a test, I tried starting with a single rectangle primitive to create the room, flipping the normals with the goal of cleaner / simpler geometry.
When I am in the room in Unreal, the sunlight seems to come through the roof after baking, even though it’s a sealed 6 poly box with only 2 point lights inside.

Is it a reasonable idea to make a single poly wall room, or is it important like S-Dot said to make at least 30cm wall thickness?

The first image below shows my original room with wall thickness vs a single 6 poly box. The second image shows the view from inside in Unreal, with the two point lights and the skylight shining through the roof. I remember something maybe blocking the back normal with 2 side geometry or something? Is that a bad idea vs a thick roof / walls?


In unreal materials by default are single sided. The light will go through the other side if you use planes only. You can use a double sided material but don’t. Better to use 2 polygons instead of a double sided material unless it’s a tree leaf and you have to.

I suggested to split inside and outside walls only for the lightmap resolution. So you don’t waste your lightmap space for something you don’t see. The thickness is just an estimate. If a thinner wall works then it’s fine. But in reality this wall would be quite thick.

Thanks for reply, I really appreciate it.

When you say split inside and outside walls… Do you mean interior ‘side’ of outer walls? I’m modeling one big open room, so maybe that doesn’t apply?
It is a HUGE room though.

I’ve been reading and experimenting all day, but really struggling. Would love any quick tip here.
The room is really big, so wondering if I should model 4 separate walls, plus a ceiling / floor separate?
See attached image of room of what I’m trying to model, and let me me know if you have any suggestions?


I was just looking at this crazy thread and I see it’s not always easy to make the right.
https://forums.unrealengine.com/development-discussion/architectural-and-design-visualization/1360944-wall-room-house-workflow

Just model the thing as it is in real life, It will take out all speculation and wondering.
Just build a wall with 6 faces then unwrap and you should be fine. If you are creating a game that will be public, then I would worry more about performance and so on, in that case you’ll need to take in consideration many more thing than just how to model the wall.
Just build everything as it should be in real life and you should be OK.

OK thanks @fco3d :slight_smile:

When importing from Blender, two of the axes need to be set from within Blender to Unreal’s axes (or transformation planes x, y, and z). So, after clicking Export > FBX, look to the right (in Blender interface) and a bit past halfway down is 3 settings: Apply Scaling, Forward, and Up. Change Forward to either X or -X, and Up to Z.

Another issue with light leaking is the volumetric lightmap. Look it up in the docs of Unreal and read the main page for it. It’s not often discussed in the forums it seems (in my experience, which is limited), but it is essential to building a scene, whether it’s for a game or ArchViz. Read and re-read the page for it to comprehend what it’s doing functionally and it’ll help with troubleshooting lighting and knowing where certain lighting is coming from.

Thanks for the tips @presto423
Still working on this with so / so results, so I appreciate your reply!