How to Fix AI Anatomy Errors: Hands, Faces, and Bodies Complete Guide 2025

AI anatomy errors are the biggest tell that an image is AI-generated. Extra fingers, merged limbs, distorted faces—these issues plague even the best models. But they're fixable. Here's how to both prevent and repair anatomy problems.

Quick Answer: Fix AI anatomy through: inpainting (redraw specific areas), using anatomy-focused negative prompts, employing better models (Pony, CyberRealistic), leveraging ControlNet for pose guidance, and post-processing with specialized tools. Prevention is easier than fixing—configure correctly before generating.

Why AI Struggles with Anatomy

Understanding the problem helps solve it:

Training Data Issues

AI models learn from images. When those images show:

• Varied hand positions (complex to learn)
• Overlapping body parts
• Unusual angles

The model gets confused. It hasn't "learned" anatomy—it's learned patterns that sometimes look like anatomy.

Diffusion Process Problems

During generation:

• Early steps establish basic structure
• Later steps add detail
• If structure is wrong early, details can't fix it
• Hands/faces are high-detail areas prone to errors

Why Hands Are Hardest

Hands are uniquely difficult because:

• Five fingers (specific number matters)
• Complex articulation
• Often small in frame
• Position varies dramatically
• Often partially occluded

The model sees thousands of hand positions but struggles to learn the consistent "five fingers" rule.

Understanding why anatomy fails helps you fix it

Prevention: Better Than Fixing

The best fix is preventing issues from occurring.

Use Better Models

For realistic anatomy:

• CyberRealistic (excellent anatomy)
• epiCRealism (strong bodies)
• Realistic Vision (balanced)

For anime:

• Pony Diffusion V6 (trained on good anatomy)
• Illustrious XL (clean results)

Avoid:

• Old SD 1.5 models for complex anatomy
• Untested models from unknown sources

Negative Prompts for Anatomy

Essential negative prompt additions:

bad anatomy, bad hands, missing fingers, extra fingers, fewer digits, extra digit, mutated hands, poorly drawn hands, malformed hands, fused fingers, too many fingers, long fingers, extra limbs, extra arms, extra legs, malformed limbs, missing arms, missing legs, extra fingers, mutated, deformed, blurry hands, cropped, out of frame, bad proportions, gross proportions, cloned face, disfigured, ugly

For faces specifically:

bad face, distorted face, asymmetric face, extra eyes, deformed eyes, missing eyes, crossed eyes, blurry face, bad teeth, missing teeth

For bodies:

bad proportions, long neck, long torso, missing limbs, extra limbs, floating limbs, disconnected limbs, mutation, deformed body

Prompt Structure for Anatomy

Structure prompts to emphasize anatomy:

Good structure:

masterpiece, best quality, [subject], detailed hands, anatomically correct, [rest of prompt]

Adding specifics:

hands at sides, hands visible, five fingers, [pose description]

Avoiding complexity:

• Simpler poses = fewer errors
• Hands at sides or behind back = easier
• Fewer overlapping body parts = cleaner results

Resolution Matters

Low resolution causes anatomy issues:

• Not enough pixels for hand details
• Faces get blocky
• Bodies look wrong

SD 1.5: Minimum 512x768 for figures SDXL/Pony: Minimum 1024x1024 or 832x1216

Higher resolution gives the model more space for details.

Inpainting: The Primary Fix

Inpainting is redrawing a specific area while keeping the rest intact.

How Inpainting Works

1. Select the problem area (mask)
2. AI regenerates only that area
3. Blends with surrounding image
4. Repeat until correct

Inpainting in ComfyUI

Basic setup:

1. Load your image
2. Add "Load Image (as Mask)" or use mask editor
3. Draw mask over problem area
4. Connect to inpaint workflow
5. Set denoise (0.5-0.8 typically)
6. Generate

Key settings:

• Denoise 0.4-0.6: Subtle changes, keeps more original
• Denoise 0.7-0.9: Significant redraw, better for major fixes
• Denoise 1.0: Complete redraw, like new generation

Prompt for inpainting: Include specific description of what you want:

detailed hand, five fingers, relaxed pose, realistic skin

Inpainting in Automatic1111

1. Go to img2img tab
2. Click "Inpaint" sub-tab
3. Upload image
4. Draw mask with brush
5. Set denoising strength
6. Write prompt for masked area
7. Generate

Tips:

• "Inpaint masked" mode
• "Mask blur" 4-8 for blending
• Match prompt to desired result

Inpainting fixes specific areas without regenerating everything

Inpainting Strategy

For hands:

1. Mask the entire hand generously
2. Include some wrist/arm
3. Denoise 0.6-0.8
4. Prompt: "detailed hand, five fingers, [position]"
5. Generate multiple, pick best
6. Repeat if needed

For faces:

1. Mask face area only
2. Include some hair/neck edge
3. Denoise 0.4-0.6 (preserve identity)
4. Prompt: focus on expression, features
5. Lower CFG sometimes helps

For bodies:

1. Mask the problem area
2. Denoise based on how much needs changing
3. Match lighting and style in prompt
4. May need multiple passes

ControlNet for Anatomy

ControlNet forces specific anatomy by using reference poses.

OpenPose Control

OpenPose detects body poses and guides generation:

1. Get pose reference

   • Use OpenPose preprocessor on reference image
   • Or create pose manually
   • Or use pose libraries

2. Configure ControlNet

   • Load OpenPose model
   • Set strength (0.7-1.0 for strict control)
   • Connect to workflow

3. Generate

   • Model follows pose guide
   • Anatomy matches reference
   • Much fewer errors

Depth Control

Depth maps help with proportions:

• Prevents floating limbs
• Maintains spatial relationships
• Good for complex scenes

Combining Controls

Use multiple ControlNet models:

• OpenPose for pose
• Depth for space
• Canny for details

More control = fewer anatomy issues.

Fixing Specific Problems

Extra/Missing Fingers

Prevention:

Negative: extra fingers, fewer digits, missing fingers, fused fingers, too many fingers, extra digit

Fix:

1. Inpaint entire hand area
2. Prompt: "detailed hand, exactly five fingers, realistic"
3. High denoise (0.7-0.8)
4. Generate multiple variations
5. Pick best or composite

Alternative: Pose hands behind back, in pockets, or obscured

Merged/Fused Limbs

Prevention:

• Simpler poses
• Fewer overlapping body parts
• Clear spatial separation in prompt

Fix:

1. Inpaint the merged area
2. Prompt clearly separated limbs
3. May need to describe each limb
4. Use ControlNet for complex fixes

Distorted Faces

Prevention:

Negative: distorted face, asymmetric face, blurry face, bad face, disfigured
Positive: detailed face, beautiful face, symmetric features

Fix:

1. Inpaint face only
2. Lower denoise (0.4-0.5) to preserve identity
3. Match expression in prompt
4. Face restoration tools (GFPGAN, CodeFormer)

Wrong Proportions

Prevention:

• Higher resolution
• Better model
• Negative prompts for proportions

Fix:

1. Inpaint larger area
2. May need body-focused model
3. ControlNet with proportion reference
4. Sometimes requires regeneration

With proper technique, most anatomy issues are fixable

Post-Processing Tools

Face Restoration

CodeFormer:

• Excellent face reconstruction
• Available in A1111 and ComfyUI
• Adjust strength to balance

GFPGAN:

• Good for general face fixes
• Fast processing
• Can over-smooth

Specialized Tools

Topaz Gigapixel:

• Paid upscaler
• Good for adding detail
• Can help with faces

Repainting manually:

• Photoshop/GIMP for final touches
• Clone stamp for small fixes
• Blend layers for compositing

Combining Multiple Outputs

When single generation fails:

1. Generate multiple versions
2. Composite best parts
3. Take hands from one, face from another
4. Blend in image editor

Model-Specific Tips

For Realistic Content

Best models:

• CyberRealistic
• epiCRealism
• Realistic Vision

Key techniques:

• Detailed negative prompts
• Higher CFG (6-8)
• More steps (30-40)
• Resolution 768+ for figures

For Anime Content

Best models:

• Pony Diffusion V6
• Illustrious XL

Key techniques:

• Danbooru-style tags
• Anime-specific negatives
• Style tags affect anatomy
• Lower CFG often (5-7)

For NSFW Content

Anatomy is especially important:

• Wrong anatomy breaks immersion
• Hands are frequently in frame
• Body proportions matter more

Recommendations:

• Use models trained on anatomy (Pony, CyberRealistic)
• Or use platforms with quality control (Apatero)
• Extra time on inpainting fixes
• Multiple generation passes

Workflow for Quality Anatomy

Step 1: Setup

• Choose appropriate model
• Include anatomy negatives
• Set proper resolution

Step 2: Initial Generation

• Generate multiple variations (5-10)
• Keep anatomy issues minimal
• Select best starting point

Step 3: First Fix Pass

• Inpaint obvious problems
• Focus on worst issues first
• Save intermediate results

Step 4: Detail Pass

• Fine-tune remaining issues
• Lower denoise for subtle fixes
• May need specialized tools

Step 5: Final Quality Check

• Zoom to 100%
• Check all hands visible
• Verify face consistency
• Review body proportions

When to Regenerate vs Fix

Fix When:

• Only one or two problems
• Overall image is good
• Inpainting area is small
• Problem is clear (extra finger, etc.)

Regenerate When:

• Multiple anatomy issues
• Fundamental pose problem
• Proportions are severely wrong
• Fixing would take longer than regenerating

Time-to-Quality Ratio

Quick check:

• Simple hand fix: 2-5 minutes
• Face adjustment: 1-3 minutes
• Major body repair: 10-15 minutes
• Full regeneration: 1-2 minutes

If fixing takes longer than regenerating several times, regenerate.

Frequently Asked Questions

Why does AI struggle with hands?

Hands have specific structure (five fingers) that varies dramatically across poses. The model learns patterns, not rules, so it doesn't "know" five fingers is correct.

Can I completely prevent anatomy issues?

No, but you can minimize them significantly. Even the best models occasionally produce errors. Build fixing into your workflow.

What's the fastest way to fix hands?

Inpainting with high denoise (0.7-0.8) and specific hand prompt. Generate 3-5 variations, pick the best. Usually takes 2-5 minutes.

Do newer models have better anatomy?

Generally yes. SDXL-based models (Pony, Illustrious) are significantly better than SD 1.5 models. But no model is perfect.

Should I use ControlNet for every generation?

Not necessarily. For simple poses, good prompts are enough. Use ControlNet for complex poses, multiple figures, or when you need specific positioning.

Is it better to fix or hide problem areas?

If you can naturally hide it (hands in pockets, hair over part of face), that's often faster. But for important images, fixing produces better results.

Recommended Workflow

For production content:

1. Use quality model (Pony, CyberRealistic, or cloud platform like Apatero)
2. Include comprehensive negative prompts
3. Generate at appropriate resolution
4. Batch generate, curate best
5. Inpaint remaining issues
6. Final quality check
7. Output

For quick generation:

1. Simpler poses (fewer anatomy challenges)
2. Strategic composition (hands less visible)
3. Accept minor imperfections
4. Fix only obvious issues

Final Thoughts

AI anatomy errors are common but manageable. The key is:

1. Prevention: Good models, proper negatives, appropriate resolution
2. Selection: Generate multiple, pick the best starting point
3. Inpainting: Fix specific areas efficiently
4. Acceptance: Some imperfection is normal—fix what matters

Every AI creator deals with anatomy issues. The difference between amateur and professional output is knowing how to fix them efficiently.

Build fixing into your workflow rather than hoping for perfect generations. With practice, you'll spend less time fixing and produce better results overall.

Related guides: ComfyUI Beginners Guide, Stable Diffusion NSFW Settings, Character Consistency Guide