Arnold Adaptive Sampling Fails to Converge in Maya 2025–2026

Arnold Adaptive Sampling Fails to Converge in Maya 2025–2026

The render stops before completion and the Script Editor displays the message Arnold error: Adaptive sampling did not converge (error code 1002). The render finishes with a partial image or a black frame, indicating that the adaptive sampling process aborted.

Diagnostic Overview

Adaptive sampling attempts to allocate more rays where image noise is high, but it can abort for several reasons. The following table summarizes the most common causes and the symptom you will see in the console.

Cause	Symptom
Adaptive Sampling disabled in Render Settings	Error 1002 appears immediately; render uses uniform sampling.
Max Samples set too low (≤ 1)	Render aborts instantly; no progress shown.
Insufficient GPU memory (VRAM < 8 GB for GPU renders)	Render stops with out‑of‑memory error or partial image.
Very high ray depth or complex shaders increase sampling cost	Convergence threshold not reached within Max Samples, leading to error 1002.

Step‑by‑Step Checks

1. Confirm Maya and Arnold version compatibility.
   1. Open the Script Editor (Windows → Settings/Preferences → Script Editor) and run:
      

      arnold -version

   2. Required permission: user must have access to the Maya installation directory (typically admin rights on Windows, sudo on macOS/Linux).
   3. Placeholder: replace Arnold 7.2.1 with the version shown.
   4. Expected check: the output should indicate Arnold 7.x, which is required for Maya 2025–2026.
   5. Risk: using an older Arnold (e.g., 6.x) may lack full Adaptive Sampling support and cause the error.
2. Verify that Adaptive Sampling is enabled.
   1. In the main menu choose Render Settings → Arnold → Adaptive Sampling.
   2. Ensure the checkbox “Enable Adaptive Sampling” is ticked.
   3. If the box is unchecked, the renderer falls back to uniform sampling, which can trigger error 1002 when the scene demands more rays than the uniform limit.
   4. Risk: disabling Adaptive Sampling dramatically increases render time and may still produce the same convergence error if other settings are mismatched.
3. Inspect Adaptive Sampling parameters.
   1. Locate the “Min Samples”, “Max Samples”, and “Convergence Threshold” fields.
   2. Set Min Samples to at least 1 (default) and Max Samples to a value between 4 and 1024. Example: Max Samples = 64.
   3. Use the Script Editor to query current values:
      

      getArnoldParam "adaptive_min_samples"

   4. Expected check: Min Samples ≥ 1 and Max Samples ≤ 1024; values outside this range may cause immediate abort or convergence failure.
   5. Risk: extremely low Max Samples (e.g., 1) aborts the render instantly; overly high values can exhaust GPU memory on cards with < 8 GB VRAM.
4. Monitor GPU memory usage.
   1. Open the Windows Task Manager (or Activity Monitor on macOS) and watch the “GPU Memory” column while a test render runs.
   2. Alternatively, in Maya’s Script Editor run:
      

      arnold -list gpu

   3. Required permission: read access to GPU statistics (standard user on most systems).
   4. Expected check: VRAM usage should stay below 80 % of total VRAM. If it approaches 100 %, the render may run out of memory and abort.
   5. Risk: high sample counts combined with complex shaders can push a 6 GB card beyond its limit, causing a crash.
5. Run a minimal test scene.
   1. Create a new project, add a simple sphere, a default Lambert material, and a single directional light.
   2. Set Render Settings → Arnold → Adaptive Sampling to the values you verified above.
   3. Start the render and watch the Script Editor for any error messages.
   4. Expected check: the test should finish quickly with a clean image and no error code.
   5. Risk: if the test still fails, the problem is likely deeper (version mismatch, driver issue, or hardware fault).

Fixes Tied to Findings

• If Adaptive Sampling was disabled, enable it in Render Settings. This restores the intended sampling strategy and eliminates the immediate abort.
• If Max Samples was set too low, raise it to at least 4. A higher ceiling gives the sampler more opportunities to meet the convergence threshold.
• If GPU memory is near capacity, reduce scene complexity: lower polygon count, simplify shaders, or switch to CPU rendering for the test. On a GPU with < 8 GB VRAM, consider decreasing Max Samples or using a render proxy.
• If convergence fails because ray depth or shader complexity is high, lower the Convergence Threshold (e.g., from 0.01 to 0.02) or increase Max Samples modestly. This reduces the required number of rays before the sampler declares success.

Escalation Criteria

Contact Autodesk support if, after completing all checks, the error persists. Provide the following information to speed up the review:

• Exact Maya version (e.g., 2025.1) and Arnold version (e.g., 7.2.1).
• Render Settings screenshot showing the Adaptive Sampling panel.
• Script Editor log containing the full error message and any preceding warnings.
• Hardware specifications, especially GPU model and total VRAM.
• Description of the test scene that reproduced the error.

Support may request additional diagnostics such as a full Arnold log file (arnold -log) or a review of driver versions. Until the issue is resolved, avoid rendering high‑complexity frames to prevent potential data loss.

Quick Reference Checklist

• Version check: Maya 2025+ & Arnold 7+.
• Enable Adaptive Sampling.
• Min Samples ≥ 1, Max Samples 4‑1024.
• GPU VRAM ≥ 8 GB (or reduce sample count).
• Test render of a simple scene succeeds.