Samples Settings Deep Dive (Advanced: Spatial vs. Temporal)

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This page is an advanced guide for those “having issues even following recipes” or “noticing contradictions with Epic Games official tutorials”.

Who Should Read This Page

✅ Tried Pro Rendering Guide but PC crashes
✅ Want to thoroughly understand Movie Render Queue settings
✅ Want to know the difference between Epic Games official tutorial (for Lumen) and R.Design (for Path Tracing) settings
✅ Want to understand the difference between “Spatial 64 × Temporal 32” and “Spatial 2048 × Temporal 1”

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For First-Timers

If you haven’t tried the basic recipes yet, please read Pro Rendering Guide first. This page digs deeper into the “why” of those recipes.

1. Common Confusion: Why Epic Official and R.Design Settings Differ

The Core Issue

If you learned about Movie Render Queue from Epic Games Official Tutorials, it probably said this:

“Keep Temporal Sample Count low (1-2) and increase Spatial Samples to improve anti-aliasing”

Meanwhile, R.Design Wiki recommends “Spatial 64 × Temporal 32”.

This is not a contradiction. It’s because the technologies used are different.

Target	Technology	Temporal Samples Role
Epic Official Tutorial	Lumen / Rasterization (Standard real-time CG)	For motion blur Creates afterimage effects in moving footage. Unnecessary for still images, so keep low.
R.Design (This Wiki)	Path Tracing (Physics-based photorealism)	For noise reduction Higher means less grainy noise like static. Essential even for still images.

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Conclusion

Video production with Lumen → Temporal 1-2 is correct (Epic official is right)
Still images with Path Tracing → Temporal 16-32 is correct (R.Design Wiki is right)

Depending on which technology you’re using, best practices are opposite.

2. The Essence of “Total Samples” in Path Tracing

In Path Tracing, the following formula determines image quality:

Spatial Samples × Temporal Samples = Total Samples

What are Total Samples?

“How many times per pixel do we calculate light bouncing?” - the total count.

Total Samples	Result
64	Grainy noise like static. Unusable.
256	Viewable with Denoiser ON.
512	Practical level with Denoiser ON. Standard photorealism.
1024	Usable even with Denoiser OFF. Beautiful texture.
2048	Denoiser OFF recommended. Professional top quality.
4096+	Cinema level. Used for 8K or special lighting.

Then Why Split Between Spatial and Temporal?

Theoretically, the following two give the same Total Samples (2048):

Option A: Spatial 2048 × Temporal 1 = 2048
Option B: Spatial 64 × Temporal 32 = 2048

However, GPU load distribution is completely different.

3. GPU Stability: Why Split with Temporal

Danger of Option A (High Spatial / Low Temporal)

Spatial: 2048
Temporal: 1

GPU behavior:

In 1 frame, tries to calculate 2048 light rays per pixel
Instantaneous extreme high load
GPU becomes “unresponsive”, TDR (Timeout Detection and Recovery) activates
Screen goes black, “Driver stopped but recovered successfully” error
Worst case, rendering interrupts or PC freezes

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What is TDR Crash?

Windows judges GPU as “frozen” if it doesn’t respond for 2+ seconds, and forcibly restarts the driver. This is TDR (Timeout Detection and Recovery).

High-load Path Tracing easily triggers this timeout.

Stability of Option B (Low Spatial / High Temporal)

Spatial: 64
Temporal: 32

GPU behavior:

In 1 frame, calculates 64 light rays per pixel (light)
1 frame complete → calculate 64 more in next frame
Repeat this 32 times
Finally achieve Total 2048 samples
Load distributed across frames, TDR doesn’t occur

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Benefits of Temporal Splitting

Breaks GPU load into “chunks”, preventing crashes
Same rendering time but overwhelmingly higher stability
For PCs with 8GB VRAM or less, this splitting is lifeline

4. Exception Cases: Scenes with Motion (Wind/Camera Motion)

The discussion so far assumes “completely static scenes”. If there’s motion like below, you need to change settings.

Case A: Tree Leaves Swaying in Wind

If wind settings are enabled in R.Design, high Temporal Samples function as “motion blur”.

Result:

Tree leaves blur and become blurry
“Photo-like sharpness” is lost

Solution:

Spatial: 1024 (or 2048)
Temporal: 1

Notes:

GPU crash risk increases
If crashes occur, lower Spatial to 512
Or turn OFF wind and shoot as still image (recommended)

Case B: Camera Moving Slowly

For video with camera sliding effects, similarly lower Temporal.

5. Settings Diagnosis Chart: What to Do When

Still Images (No wind, fixed camera)

VRAM	GPU	Spatial	Temporal	Total	Denoiser	Notes
6GB	RTX 3060	32	16	512	ON	Standard balanced settings. Stability priority.
8GB	RTX 4060	64	16	1024	ON/OFF	Beautiful even with Denoiser OFF.
12GB+	RTX 5070	64	32	2048	OFF	Professional top quality. Stable with Temporal split.

Video (Wind present, camera moving)

VRAM	GPU	Spatial	Temporal	Total	Denoiser	Notes
6GB	RTX 3060	256	1	256	ON	No motion blur. Lightweight settings.
8GB	RTX 4060	512	1	512	ON	Denoiser covers noise.
12GB+	RTX 5070	1024	1	1024	OFF	Watch for crashes. Test required.

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Note for Video

Setting Temporal to 1 increases crash risk. Always test render short sections (about 10 seconds) before full production.

6. Troubleshooting: Frequently Asked Questions

Q1: Following recipe but screen goes black

Cause: TDR crash occurring.

Solution:

Reduce Spatial by half (e.g., 64 → 32)
Keep Temporal same (e.g., 32)
Total Samples decrease but prioritize stability

Q2: Used Epic official settings (Temporal 1-2) but full of noise

Cause: Temporal is essential for noise reduction in Path Tracing.

Solution:

Increase Temporal to 16 or more
Or set Spatial to 1024+ (but crash risk)

Q3: Stable even with Spatial 2048 × Temporal 1. Is this correct?

Answer: If your GPU is very powerful (VRAM 16GB+, good cooling), it works. However, there are following disadvantages:

Possible sudden crashes during long renders
Unstable when other apps (Chrome etc.) open simultaneously

Recommendation: Changing to 64 × 32 gives same quality, so splitting is safer.

Summary: Philosophy of Samples

Element	Role	Adjustment Policy
Spatial Samples	Calculation density per frame	Too high causes TDR crash. Adjust based on VRAM capacity.
Temporal Samples	Load distribution count	Higher is more stable. However, causes blur if motion present.
Total Samples	Final image quality	512 practical, 1024 high quality, 2048 professional grade.

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Pro’s Rule (Recap)

Still images (no wind): Suppress Spatial, earn Total through Temporal
Video (with wind): Set Temporal to 1, secure quality with Spatial
Crashes occur: First halve Spatial. If still fails, turn Denoiser ON

Reference Links

Epic Games Official Tutorial: Movie Render Queue
Pro Rendering Guide - Basic recipes
Interior & Night Scenes - Scene-specific setting strategies
Heavy Operation & Crashes - Crash troubleshooting
System Requirements - VRAM capacity confirmation

Interior & Night Scenes