Create publication-quality scientific diagrams using Nano Banana Pro AI with smart iterative refinement. Uses Gemini 3 Pro for quality review.
Scientific schematics and diagrams transform complex concepts into clear visual representations for publication. This skill uses Nano Banana 2 AI for diagram generation with Gemini 3.1 Pro Preview quality review.
How it works:
Quality Thresholds by Document Type:
| Document Type | Threshold | Description |
|---|---|---|
| journal | 8.5/10 | Nature, Science, peer-reviewed journals |
| conference | 8.0/10 | Conference papers |
| thesis | 8.0/10 | Dissertations, theses |
| grant | 8.0/10 | Grant proposals |
| preprint | 7.5/10 | arXiv, bioRxiv, etc. |
| report | 7.5/10 | Technical reports |
| poster | 7.0/10 | Academic posters |
| presentation | 6.5/10 | Slides, talks |
| default | 7.5/10 | General purpose |
Simply describe what you want, and Nano Banana 2 creates it. All diagrams are stored in the figures/ subfolder and referenced in papers/posters.
Create any scientific diagram by simply describing it. Nano Banana 2 handles everything automatically with smart iteration:
# Generate for journal paper (highest quality threshold: 8.5/10)
python scripts/generate_schematic.py "CONSORT participant flow diagram with 500 screened, 150 excluded, 350 randomized" -o figures/consort.png --doc-type journal
# Generate for presentation (lower threshold: 6.5/10 - faster)
python scripts/generate_schematic.py "Transformer encoder-decoder architecture showing multi-head attention" -o figures/transformer.png --doc-type presentation
# Generate for poster (moderate threshold: 7.0/10)
python scripts/generate_schematic.py "MAPK signaling pathway from EGFR to gene transcription" -o figures/mapk_pathway.png --doc-type poster
# Custom max iterations (max 2)
python scripts/generate_schematic.py "Complex circuit diagram with op-amp, resistors, and capacitors" -o figures/circuit.png --iterations 2 --doc-type journal
What happens behind the scenes:
Smart Iteration Benefits:
Output: Versioned images plus a detailed review log with quality scores, critiques, and early-stop information.
Set your OpenRouter API key:
export OPENROUTER_API_KEY='your_api_key_here'
Get an API key at: https://openrouter.ai/keys
Effective Prompts for Scientific Diagrams:
✓ Good prompts (specific, detailed):
✗ Avoid vague prompts:
Key elements to include:
Scientific Quality Guidelines (automatically applied):
This skill should be used when:
Simply describe your diagram in natural language. Nano Banana 2 generates it automatically:
python scripts/generate_schematic.py "your diagram description" -o output.png
That's it! The AI handles:
Works for all diagram types:
No coding, no templates, no manual drawing required.
The AI generation system uses smart iteration - it only regenerates if quality is below the threshold for your document type:
┌─────────────────────────────────────────────────────┐
│ 1. Generate image with Nano Banana 2 │
│ ↓ │
│ 2. Review quality with Gemini 3.1 Pro Preview │
│ ↓ │
│ 3. Score >= threshold? │
│ YES → DONE! (early stop) │
│ NO → Improve prompt, go to step 1 │
│ ↓ │
│ 4. Repeat until quality met OR max iterations │
└─────────────────────────────────────────────────────┘
Prompt Construction:
Scientific diagram guidelines + User request
Output: diagram_v1.png
Gemini 3.1 Pro Preview evaluates the diagram on:
Example Review Output:
SCORE: 8.0
STRENGTHS:
- Clear flow from top to bottom
- All phases properly labeled
- Professional typography
ISSUES:
- Participant counts slightly small
- Minor overlap on exclusion box
VERDICT: ACCEPTABLE (for poster, threshold 7.0)
| If Score... | Action |
|---|---|
| >= threshold | STOP - Quality is good enough for this document type |
| < threshold | Continue to next iteration with improved prompt |
Example:
If quality is below threshold, the system:
All iterations are saved with a JSON review log that includes early-stop information:
{
"user_prompt": "CONSORT participant flow diagram...",
"doc_type": "poster",
"quality_threshold": 7.0,
"iterations": [
{
"iteration": 1,
"image_path": "figures/consort_v1.png",
"score": 7.5,
"needs_improvement": false,
"critique": "SCORE: 7.5\nSTRENGTHS:..."
}
],
"final_score": 7.5,
"early_stop": true,
"early_stop_reason": "Quality score 7.5 meets threshold 7.0 for poster"
}
Note: With smart iteration, you may see only 1 iteration instead of the full 2 if quality is achieved early!
from scripts.generate_schematic_ai import ScientificSchematicGenerator
# Initialize generator
generator = ScientificSchematicGenerator(
api_key="your_openrouter_key",
verbose=True
)
# Generate with iterative refinement (max 2 iterations)
results = generator.generate_iterative(
user_prompt="Transformer architecture diagram",
output_path="figures/transformer.png",
iterations=2
)
# Access results
print(f"Final score: {results['final_score']}/10")
print(f"Final image: {results['final_image']}")
# Review individual iterations
for iteration in results['iterations']:
print(f"Iteration {iteration['iteration']}: {iteration['score']}/10")
print(f"Critique: {iteration['critique']}")
# Basic usage (default threshold 7.5/10)
python scripts/generate_schematic.py "diagram description" -o output.png
# Specify document type for appropriate quality threshold
python scripts/generate_schematic.py "diagram" -o out.png --doc-type journal # 8.5/10
python scripts/generate_schematic.py "diagram" -o out.png --doc-type conference # 8.0/10
python scripts/generate_schematic.py "diagram" -o out.png --doc-type poster # 7.0/10
python scripts/generate_schematic.py "diagram" -o out.png --doc-type presentation # 6.5/10
# Custom max iterations (1-2)
python scripts/generate_schematic.py "complex diagram" -o diagram.png --iterations 2
# Verbose output (see all API calls and reviews)
python scripts/generate_schematic.py "flowchart" -o flow.png -v
# Provide API key via flag
python scripts/generate_schematic.py "diagram" -o out.png --api-key "sk-or-v1-..."
# Combine options
python scripts/generate_schematic.py "neural network" -o nn.png --doc-type journal --iterations 2 -v
1. Be Specific About Layout:
✓ "Flowchart with vertical flow, top to bottom"
✓ "Architecture diagram with encoder on left, decoder on right"
✓ "Circular pathway diagram with clockwise flow"
2. Include Quantitative Details:
✓ "Neural network with input layer (784 nodes), hidden layer (128 nodes), output (10 nodes)"
✓ "Flowchart showing n=500 screened, n=150 excluded, n=350 randomized"
✓ "Circuit with 1kΩ resistor, 10µF capacitor, 5V source"
3. Specify Visual Style:
✓ "Minimalist block diagram with clean lines"
✓ "Detailed biological pathway with protein structures"
✓ "Technical schematic with engineering notation"
4. Request Specific Labels:
✓ "Label all arrows with activation/inhibition"
✓ "Include layer dimensions in each box"
✓ "Show time progression with timestamps"
5. Mention Color Requirements:
✓ "Use colorblind-friendly colors"
✓ "Grayscale-compatible design"
✓ "Color-code by function: blue for input, green for processing, red for output"
python scripts/generate_schematic.py \
"CONSORT participant flow diagram for randomized controlled trial. \
Start with 'Assessed for eligibility (n=500)' at top. \
Show 'Excluded (n=150)' with reasons: age<18 (n=80), declined (n=50), other (n=20). \
Then 'Randomized (n=350)' splits into two arms: \
'Treatment group (n=175)' and 'Control group (n=175)'. \
Each arm shows 'Lost to follow-up' (n=15 and n=10). \
End with 'Analyzed' (n=160 and n=165). \
Use blue boxes for process steps, orange for exclusion, green for final analysis." \
-o figures/consort.png
python scripts/generate_schematic.py \
"Transformer encoder-decoder architecture diagram. \
Left side: Encoder stack with input embedding, positional encoding, \
multi-head self-attention, add & norm, feed-forward, add & norm. \
Right side: Decoder stack with output embedding, positional encoding, \
masked self-attention, add & norm, cross-attention (receiving from encoder), \
add & norm, feed-forward, add & norm, linear & softmax. \
Show cross-attention connection from encoder to decoder with dashed line. \
Use light blue for encoder, light red for decoder. \
Label all components clearly." \
-o figures/transformer.png --iterations 2
python scripts/generate_schematic.py \
"MAPK signaling pathway diagram. \
Start with EGFR receptor at cell membrane (top). \
Arrow down to RAS (with GTP label). \
Arrow to RAF kinase. \
Arrow to MEK kinase. \
Arrow to ERK kinase. \
Final arrow to nucleus showing gene transcription. \
Label each arrow with 'phosphorylation' or 'activation'. \
Use rounded rectangles for proteins, different colors for each. \
Include membrane boundary line at top." \
-o figures/mapk_pathway.png
python scripts/generate_schematic.py \
"IoT system architecture block diagram. \
Bottom layer: Sensors (temperature, humidity, motion) in green boxes. \
Middle layer: Microcontroller (ESP32) in blue box. \
Connections to WiFi module (orange box) and Display (purple box). \
Top layer: Cloud server (gray box) connected to mobile app (light blue box). \
Show data flow arrows between all components. \
Label connections with protocols: I2C, UART, WiFi, HTTPS." \
-o figures/iot_architecture.png
The main entry point for generating scientific schematics:
# Basic usage
python scripts/generate_schematic.py "diagram description" -o output.png
# Custom iterations (max 2)
python scripts/generate_schematic.py "complex diagram" -o diagram.png --iterations 2
# Verbose mode
python scripts/generate_schematic.py "diagram" -o out.png -v
Note: The Nano Banana 2 AI generation system includes automatic quality review in its iterative refinement process. Each iteration is evaluated for scientific accuracy, clarity, and accessibility.
\includegraphics{} for generated imagesProblem: Overlapping text or elements
--iterations 2 for better refinementProblem: Elements not connecting properly
Problem: Export quality poor
--iterations 2Problem: Elements overlap after generation
--iterations 2 for better refinementProblem: False positive overlap detection
detect_overlaps(image_path, threshold=0.98)Problem: Generated image quality is low
--iterations 2Problem: Colorblind simulation shows poor contrast
Problem: High-severity overlaps detected
Problem: Visual report generation fails
Image.open(path).verify()Problem: Colors indistinguishable in grayscale
verify_accessibility(image_path)Problem: Text too small when printed
validate_resolution(image_path)Problem: Accessibility checks consistently fail
Load these files for comprehensive information on specific topics:
references/diagram_types.md - Catalog of scientific diagram types with examplesreferences/best_practices.md - Publication standards and accessibility guidelinesPython Libraries
Publication Standards
This skill works synergistically with:
Before submitting diagrams, verify:
run_quality_checks() and achieved PASS statusquality_reports/ directory\ref{} points to correct figure)# Required
export OPENROUTER_API_KEY='your_api_key_here'
# Get key at: https://openrouter.ai/keys
Simplest possible usage:
python scripts/generate_schematic.py "your diagram description" -o output.png
Use this skill to create clear, accessible, publication-quality diagrams that effectively communicate complex scientific concepts. The AI-powered workflow with iterative refinement ensures diagrams meet professional standards.