Beginner‑friendly steps to install a 16K GLB skydome (visual background) and to import/use 16K HDR/EXR for realistic image‑based lighting in Unreal Engine 5.6.

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What you’ll accomplish:

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• Add a GLB skydome for a beautiful 360° background.

• Light your scene using HDR/EXR via HDRI Backdrop or a SkyLight.

• Apply best‑practice import presets, fix common issues, and optimize performance.

 

A) Install a 16K .GLB skydome (visual background only)

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Use this when you want a fast, high‑fidelity sky backdrop. Lighting will come from HDR/EXR (Sections B/C).

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1.  Import the GLB

• Open your project → Content Drawer → Add (+) → Import to…

• Select your .glb file → Import All.

• UE will create a Static Mesh and (if present inside the GLB) embedded Texture/Material assets automatically.

2.  Create (or verify) the Skydome Material

If the GLB brought in a material, open it and confirm:

• Shading Model: Unlit

• Two Sided: Enabled

• Embedded texture feeds Emissive Color.

If you need to make a new one:

• Right‑click → Material → name it M_Skydome_Unlit → Unlit + Two‑Sided On; add a Texture Sample (embedded sky) → Emissive Color → Apply.

3.  Assign the Material to the Skydome Mesh

• Open the Static Mesh (Static Mesh Editor).

• In Materials, set Element 0 = M_Skydome_Unlit (or the verified imported material).

• Set Collision Presets = NoCollision → Save.

4.  Place and Scale the Dome

• Drag the mesh into your level.

• Details: Location X=0, Y=0, Z=0; Scale e.g., (1000, 1000, 1000) — increase for larger scenes.

• Press Play to preview.

If the image looks soft or you see a seam

• Open the imported Texture asset (from the GLB):

• Mip Gen Settings: NoMipmaps or Sharpen

• Address X/Y: Clamp

 

(Optional) Add a Multiply in the material before Emissive (e.g., 1.5–2.0) to brighten.

 

B) Light your scene with a 16K .HDR/.EXR using HDRI Backdrop (background + lighting)

 

Use this to get realistic lighting and a matching background from a single asset—ideal for look‑dev and product shots.

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5.  Enable once: HDRI Backdrop plugin

• Edit → Plugins → search “HDRI Backdrop” → Enable → restart if prompted.

6.  Import the HDR/EXR

• Add (+) → Import to… → choose your .hdr or .exr.

• Open the imported texture and set:

• sRGB: Off (linear HDR)

• Compression Settings: HDR (RGB, no alpha)

• (Optional) Keep default Mip Gen unless you see banding.

7.  Add HDRI Backdrop to the level

• Place Actors → search HDRI Backdrop → drag into the level.

Details:

• Cubemap/HDRI: assign your imported HDR/EXR

• Intensity: start 1.0–2.0

• Size: 10,000–20,000 (enclose scene)

• Rotation (Yaw): aim the key direction you want.

8.  Exposure sanity check

• Add a Post Process Volume → Infinite Extent (Unbound).

• In Exposure, set Manual and tune Exposure Compensation if too dark/bright.

9.  Reflections and lighting

• For Lumen: updates are immediate.

• For baked/legacy: add Reflection Capture (Sphere/Box) and Build lighting or Recapture as needed.

10.  Quality notes

• Prefer .EXR for maximum dynamic range and cleaner speculars.

• Keep 16K masters; create 8K/4K working copies for iteration if needed.

 

C) Light your scene with a SkyLight (HDR/EXR lighting only) + your own background

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Use this when you want physical lighting from the HDR/EXR but keep a custom background (GLB dome, fog, matte painting).

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11.  Import the HDR/EXR (as in B‑2)

• Set sRGB Off and Compression = HDR.

12.  Add/Select a SkyLight

• Place Actors → SkyLight (or select existing).

• Details: Source Type = Specified Cubemap; assign your HDR/EXR (UE may create a TextureCube — accept).

• Intensity: begin at 0.5–2.0 to taste.

13.  Refresh reflections / lighting

• Toggle Real Time Capture (costly) or click Recapture.

• With Lumen on, highlights respond immediately.

14.  Combine with your GLB

• Keep the GLB skydome visible as background.

• Let the SkyLight provide illumination and reflections.

 

UE 5.6 Import & Asset Presets (Recommended)

 

Apply these once, then use as a checklist:

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• GLB Static Mesh: Collision = NoCollision; Keep Normals; Import Materials = On; Two‑Sided in sky material.

• Skydome Material: Shading Model = Unlit; Two Sided = On; Emissive = Texture (optional Multiply for brightness).

• HDR/EXR Texture: sRGB = Off; Compression = HDR (RGB, no alpha); Mip Gen = Default (or test Sharpen if banding).

• HDRI Backdrop: Intensity 1.0–2.0; Size 10,000–20,000; Yaw for sun direction.

• SkyLight (Specified Cubemap): assign HDR/EXR; Intensity 0.5–2.0; Recapture after big changes.

• Post Process Volume: Infinite Extent (Unbound); Exposure = Manual; adjust Exposure Compensation.

 

Which path should I use?

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• Fastest pretty background (no extra setup): GLB only (Section A).

• Realistic lighting + matching background from one asset: HDRI Backdrop with HDR/EXR (Section B).

• Custom background (GLB/atmosphere) + physical lighting: SkyLight with HDR/EXR (Section C).

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FAQ

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Q: Do I need JPG/PNG assets?

A: No. Your GLB, HDR, and EXR contain everything you need. The GLB’s embedded textures import directly into UE.

Q: Should I always use 16K at runtime?

A: Keep 16K masters for final rendering. For iteration or real‑time performance, create 8K/4K down‑res copies.

Q: EXR vs HDR — which is better?

A: EXR generally offers cleaner highlights and wider dynamic range. Use HDRI Backdrop or SkyLight with EXR for best results.

Q: My sun direction is wrong. How do I rotate it?

A: Rotate the HDRI Backdrop (Yaw) or rotate the SkyLight’s capture (using a rotated cube or by re‑authoring HDRI orientation).

Q: Can I mix GLB backdrop with HDRI lighting?

A: Yes. Keep the GLB for visuals (Section A) and drive lighting with a SkyLight or HDRI Backdrop (Sections B/C).