Interior & Night Scene Rendering

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Interior scenes, especially night scenes, are a completely different battle from exteriors (daytime). This page explains three interior-specific strategies to eliminate “grainy noise like static”.

Interior Night Sample Example: 4K / 4096 Samples / Denoiser ON

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Prerequisites

This page is an advanced guide for those who understand the basic recipes in Pro Rendering Guide. If you haven’t tried the basics yet, please read that first.

Why Are Interior Scenes Difficult?

Exteriors (day) and interiors (night) have vastly different complexity of light calculations.

Exteriors (Day)

Light Source: The sun, an extremely large and powerful light source
Light Path: Reaches camera directly
Calculation: Simple, less prone to noise

Interiors (Night)

Light Source: Small lights (Point Light, Spot Light)
Light Path: Bounces off walls and floors multiple times before reaching camera
Calculation: Complex, very prone to noise

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Conclusion

Rendering interiors with the same settings as exteriors will leave “grainy noise like static”. Interiors require interior-specific strategies.

Strategy 1: Denoiser ON (Recommended & Balanced)

While we recommended “Denoiser OFF for textures” for exteriors, persisting with Denoiser OFF in dark interior scenes with insufficient light is not realistic due to excessive calculation time.

For interiors specifically, turning “Denoiser ON” is the smart choice.

Recommended Settings Recipe (Copy-Paste Ready)

✓ Rendering Mode: Pathtracer
✓ Resolution: 3840x2160 (4K)
✓ Use Denoiser: ON ← OK for interiors!
✓ Spatial Samples: 64
✓ Temporal Samples: 32 (Total 2048 samples)
✓ Upscaler Algorithm: None

Key Points

Denoiser ON eliminates static
However, maintain high sample count (2048)
By “providing clean information to the denoiser,” prevents painted appearance

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Recommendation: ★★★★★

Try this setting first. Even RTX 3060 (VRAM 8GB) class can complete beautiful images in about 10-20 minutes.

Strategy 2: Multiply Sample Count (Premium Quality & Brute Force)

If you “absolutely want to avoid using denoiser and maintain that rich texture,” you need even higher sample count than exteriors.

Reason

Eliminating noise in areas where light doesn’t reach (dark areas) requires several times more calculations than exteriors.

Recommended Settings Recipe (Advanced)

✓ Rendering Mode: Pathtracer
✓ Resolution: 3840x2160 (4K)
✓ Use Denoiser: OFF ← Completely preserves texture
✓ Spatial Samples: 64 (or 128)
✓ Temporal Samples: 64 (Total 4096 samples)
✓ Upscaler Algorithm: None

For even higher:

Spatial: 128
Temporal: 64
Total: 8192 samples

Rendering Time Estimates

PC	VRAM	4096 Samples	8192 Samples
RTX 3060	8GB	30-60 min	60-120 min
RTX 4070	12GB	20-40 min	40-80 min
RTX 5070	12GB	15-30 min	30-60 min

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Note

This is for professional final output. Takes time, but this is the only way to physically eliminate noise. Only try this if you’re not satisfied with “Strategy 1”.

Strategy 3: Light Settings Optimization

A common trap for CG beginners is “light Intensity values too low, forcibly brightening only with camera ISO sensitivity”. This produces massive noise.

Checklist

Check Unreal Engine light settings
- Are Point Light or Spot Light Intensity at low values (e.g., 5, 10)?
Check camera exposure settings
- Is Exposure Compensation at very high values (e.g., +3, +5)?
- 👉 Reference: Camera Settings

Correct Balance

Bad Example (High Noise)	Good Example (Low Noise)
Light Intensity: 5 Exposure Compensation: +5	Light Intensity: 50 Exposure Compensation: 0

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Pro’s Rule

Adjust to a balance of “strengthen lights and lower exposure”. Stronger light energy reduces noise during calculation.

Specific Adjustment Steps

Select light and increase Intensity by 10x~50x
Return Exposure Compensation to 0 in camera settings
If too bright, slightly lower light value (not exposure)

Which Strategy to Try First? (Flowchart)

Step 1: Try Strategy 1 First

Denoiser ON / Samples 2048
↓
Render (10-20 min)
↓
Check result

Step 2: Evaluate Result

Evaluation	Next Action
◎ Satisfied!	Done! Proceed to production with these settings.
○ Noise eliminated but texture slightly lacking	→ Try Strategy 2 (Samples 4096)
△ Noise still remains	→ Check Strategy 3 (Light optimization)
× Overall dark / High noise	→ Prioritize Strategy 3 (Light optimization)

Conclusion: Settings to Use Right Now

First, try “Strategy 1 (Balanced)”. This should make it sufficiently beautiful.

✓ Use Denoiser: ON (OK for interiors!)
✓ Spatial Samples: 64
✓ Temporal Samples: 32 (Total 2048 samples)
✓ Resolution: 3840x2160 (4K)

Try rendering once with this. Static should disappear, and high sample count preserves decent texture.

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Success Point

Exteriors (Day): Denoiser OFF / Samples 2048
Interiors (Night): Denoiser ON / Samples 2048 ← This is correct!

Master using denoiser appropriately for each scene.

Frequently Asked Questions

Q. Is it bad to use Denoiser ON for exteriors too?

A. Not bad, but exteriors (day) have strong light, so Denoiser OFF can eliminate noise in relatively short time. To maximize texture, OFF is recommended for exteriors.

Q. What if noise remains even with Samples 2048?

A. Check the following:

Is light Intensity too low? (Strategy 3)
Are there too many glass/mirrors? (Many reflections increase noise)
Is the room abnormally large? (Light doesn’t reach)

If still remaining, increase Samples to 4096.

Q. Rendering stops midway / Crashes

A. Spatial Samples may be too high.

Lower Spatial to 32
Raise Temporal to 64 (Total remains same)
For details → Samples Settings Deep Dive

Basic Recipe: Pro Rendering Guide
Advanced: Samples Settings Deep Dive (Advanced)
Camera Settings: Camera Settings (Exposure/Focus)
Crash Prevention: Heavy Operation & Crashes

Pro Rendering Guide Samples Settings Deep Dive (Advanced)