Game Concept Art

Iterative visual development using ComfyUI for concept art, character design, environment painting, storyboards, and visual exploration. This skill covers organized workflows for generating, iterating, and managing concept art across game projects.

Infrastructure

ComfyUI runs on a GPU workstation accessible over the network (or locally).

Detail	Value
Web UI	`${COMFYUI_BASE_URL}` (default: `http://localhost:8188`)
API	`${COMFYUI_BASE_URL}/api`
Models	FLUX 1 Schnell, FLUX 2 Klein (4B/9B), FLUX 2 Dev
Text encoders	CLIP, Mistral, Qwen 3 (4B/8B), T5 XXL
Output dir	Configured in ComfyUI settings (default: `./output/`)

Set the COMFYUI_BASE_URL environment variable to point to your ComfyUI instance. Defaults to http://localhost:8188.

VRAM guidelines: Adjust based on your GPU. A 12GB card can run FLUX 9B at 1024px comfortably; 1536px will push the limit. A 16GB+ card gives more headroom for larger models and resolutions.

Available models

Model	Size	Speed	Quality	Best for
flux1-schnell	Fast	Fastest	Good	Rapid exploration, thumbnails
flux-2-klein-4b-fp8	4B	Fast	Good	Quick iteration, batch concepts
flux-2-klein-9b-fp8	9B	Medium	High	Refined concepts, hero images
flux2_dev_fp8mixed	Full	Slow	Highest	Final concept art, presentations

Text encoders by quality tier:

Quick iteration: CLIP + T5 XXL
Standard: CLIP + Qwen 3 4B + T5 XXL
Maximum: CLIP + Mistral + Qwen 3 8B + T5 XXL

ComfyUI API usage

Queue a prompt (generate an image)

POST ${COMFYUI_BASE_URL}/prompt
{
  "prompt": { <workflow JSON nodes> },
  "client_id": "agent-concept-art"
}

The workflow JSON is a node graph. Key nodes for concept art:

Minimal text-to-image workflow

{
  "1": {
    "class_type": "CheckpointLoaderSimple",
    "inputs": { "ckpt_name": "flux1-schnell.safetensors" }
  },
  "2": {
    "class_type": "CLIPTextEncode",
    "inputs": { "text": "your prompt here", "clip": ["1", 1] }
  },
  "3": {
    "class_type": "CLIPTextEncode",
    "inputs": { "text": "blurry, low quality, text, watermark", "clip": ["1", 1] }
  },
  "4": {
    "class_type": "EmptyLatentImage",
    "inputs": { "width": 1024, "height": 1024, "batch_size": 1 }
  },
  "5": {
    "class_type": "KSampler",
    "inputs": {
      "model": ["1", 0],
      "positive": ["2", 0],
      "negative": ["3", 0],
      "latent_image": ["4", 0],
      "seed": 42,
      "steps": 20,
      "cfg": 7.0,
      "sampler_name": "euler",
      "scheduler": "normal"
    }
  },
  "6": {
    "class_type": "VAEDecode",
    "inputs": { "samples": ["5", 0], "vae": ["1", 2] }
  },
  "7": {
    "class_type": "SaveImage",
    "inputs": { "images": ["6", 0], "filename_prefix": "concept/char_hero" }
  }
}

Check generation status

GET ${COMFYUI_BASE_URL}/history/{prompt_id}

Get generated image

GET ${COMFYUI_BASE_URL}/view?filename={filename}&subfolder={subfolder}&type=output

Interrupt current generation

POST ${COMFYUI_BASE_URL}/interrupt

Iteration workflow

Concept art is iterative. Follow this structured approach:

Phase 1: Exploration (wide, fast)

Generate many rough variants to find promising directions.

Model: flux1-schnell or flux-2-klein-4b
Steps: 8-12
Resolution: 512x512 or 768x768
Batch size: 4-8 per prompt
Naming: {project}/{category}_explore_{concept}_{number}
Goal: 20-40 thumbnails across varied prompts

Example exploration naming:

myproject/char_explore_survivor_00001.png
myproject/char_explore_survivor_00002.png
myproject/env_explore_ruins_00001.png

Phase 2: Refinement (narrow, quality)

Take the best directions and iterate with better parameters.

Model: flux-2-klein-9b or flux2_dev
Steps: 20-30
Resolution: 1024x1024 or 1024x1536
Batch size: 2-4
Naming: {project}/{category}_refine_{concept}_{number}
Seed locking: Fix the seed from exploration, vary prompt details

myproject/char_refine_survivor_00001.png
myproject/char_refine_survivor_00002.png

Phase 3: Final (hero images)

Polish selected concepts for presentation or handoff.

Model: flux2_dev_fp8mixed
Steps: 30-50
Resolution: 1536x1536 or 1024x2048 (depending on format)
Batch size: 1
Naming: {project}/{category}_final_{concept}_{number}

myproject/char_final_survivor_00001.png

Output organization

Folder structure by project

output/
  {project}/
    characters/
      char_explore_{name}_{NNNNN}.png
      char_refine_{name}_{NNNNN}.png
      char_final_{name}_{NNNNN}.png
      char_sheet_{name}_{NNNNN}.png      -- Character sheets
      char_turnaround_{name}_{NNNNN}.png -- Turnaround views
    environments/
      env_explore_{name}_{NNNNN}.png
      env_refine_{name}_{NNNNN}.png
      env_final_{name}_{NNNNN}.png
      env_mood_{name}_{NNNNN}.png        -- Mood/lighting studies
    storyboards/
      sb_{scene}_{shot}_{NNNNN}.png      -- Storyboard frames
      sb_{scene}_layout_{NNNNN}.png      -- Scene layouts
    props/
      prop_{name}_{NNNNN}.png
    ui/
      ui_{screen}_{NNNNN}.png
    mood/
      mood_{theme}_{NNNNN}.png           -- Mood boards, color palettes

Use the filename_prefix parameter in ComfyUI's SaveImage node to route output to the right folder automatically.

Prompt engineering for concept art

Structure

{subject}, {style}, {composition}, {lighting}, {mood}, {medium}, {details}

Style keywords by art direction

Direction	Keywords
Painterly	oil painting, visible brushstrokes, impressionistic, painterly
Clean digital	digital painting, clean lines, polished, concept art, artstation
Sketch	pencil sketch, rough, gestural, line art, hatching
Realistic	photorealistic, hyperdetailed, 8k, ray tracing
Stylized	stylized, cel shaded, low poly, flat color, graphic
Dark/gritty	dark fantasy, grimdark, muted palette, weathered, grungy
Vibrant	vivid colors, saturated, high contrast, colorful

Negative prompt defaults

Always include quality negatives unless seeking a specific rough style:

blurry, low quality, jpeg artifacts, text, watermark, signature,
deformed, disfigured, bad anatomy, extra limbs, mutated

Character design prompts

# Full body character sheet
"full body character concept art, {character description},
front view and side view, character sheet, white background,
clean design, game character, {style keywords}"

# Portrait / headshot
"portrait of {character description}, bust shot,
detailed face, {expression}, {lighting}, concept art, {style}"

# Action pose
"{character description}, dynamic action pose, {action},
{environment context}, dramatic lighting, concept art"

# Turnaround
"character turnaround sheet, {character description},
front view, three-quarter view, side view, back view,
orthographic, character design, white background"

Environment design prompts

# Establishing shot
"wide landscape, {environment description}, {time of day},
{weather}, {mood}, environment concept art, matte painting style"

# Key location
"{location type}, {architectural style}, {materials},
{lighting condition}, {mood}, game environment concept art,
detailed, atmospheric perspective"

# Color/mood study
"color key painting, {scene description}, {dominant colors},
{time of day}, {mood adjectives}, loose brushwork,
environment mood study"

# Cross-section / layout
"cross-section view of {building/structure}, interior layout,
cutaway illustration, architectural diagram, concept art"

Storyboard prompts

# Single frame
"storyboard frame, {shot type}: {action description},
{camera angle}, cinematic composition, black and white sketch,
film storyboard style"

# Shot types: extreme wide, wide, medium, close-up, extreme close-up,
#   over-the-shoulder, bird's eye, worm's eye, dutch angle

# Emotional beat
"cinematic frame, {character} {emotion/action},
{lighting mood}, dramatic, film still composition,
concept art, {color palette}"

Prop and item design

# Weapon/tool
"{item type} design sheet, {description}, multiple angles,
orthographic views, detailed, game prop concept art,
white background, {material} surface"

# Inventory item
"game item icon, {item description}, isometric view,
stylized, clean rendering, game UI icon style"

Sampler and parameter guide

Use case	Sampler	Steps	CFG	Scheduler
Fast exploration	euler	8-12	5-7	normal
Standard quality	euler_ancestral	20	7	normal
High detail	dpmpp_2m_sde	25-30	7-8	karras
Maximum quality	dpmpp_2m_sde	40-50	7	karras
Consistent iteration	euler	20	7	normal

Seed management

Exploration: Random seeds (let ComfyUI auto-generate)
Refinement: Lock the seed from a good exploration result, adjust prompt
Variations: Increment seed by 1 from a good result for similar-but-different outputs
Record seeds: Always note the seed of outputs you like -- it's your "undo" for regeneration

Aspect ratios

Format	Resolution	Use case
Square	1024x1024	Character portraits, icons, mood boards
Portrait	832x1216	Full-body characters, vertical environments
Landscape	1216x832	Environment establishing shots, panoramas
Wide	1536x640	Storyboard frames, cinematic compositions
Tall	640x1536	Vertical scenes, tower/cliff environments
Sheet	1536x1024	Character sheets, turnarounds, multi-view

Keep dimensions divisible by 8. FLUX models work well at 1024-1536px range.

Batch iteration patterns

A/B prompt comparison

Generate the same seed with two different prompts to compare specific changes:

Prompt A: "medieval knight, steel armor, battle-worn"
Prompt B: "medieval knight, leather armor, battle-worn"
Same seed, same parameters -- only the prompt differs

Style exploration

Same subject, different style keywords:

"hero character, oil painting, classical"
"hero character, cel shaded, anime inspired"
"hero character, pencil sketch, rough concept"
"hero character, digital painting, artstation trending"

Lighting studies

Same scene, different lighting:

"forest ruins, golden hour, warm light"
"forest ruins, moonlight, cool blue tones"
"forest ruins, overcast, diffused light, muted"
"forest ruins, dramatic storm, volumetric lightning"

Working with the game design team

Concept brief format

When receiving a design brief (from the game-designer skill or director):

Extract visual keywords: Characters, props, locations, mood, references
Define scope: How many concepts? Which categories? What fidelity?
Exploration round: Generate 20-40 thumbnails across directions
Present options: Organize by direction, annotate with brief notes
Refine selected: Iterate on approved directions at higher quality
Deliver finals: Export hero images for handoff to 3D or further development

Handoff to other skills

To character pipeline: Final character concepts as reference for modeling/rigging
To level design: Environment concepts as reference for world building
To cinematics: Storyboard frames as shot planning reference
To team documentation: Upload approved concepts to shared project docs for team access

Requesting feedback

When presenting concepts to the director/operator:

Show exploration thumbnails grouped by direction
Call out your recommended top 3 with brief rationale
Ask specific questions: "Should the armor be heavier?" not "What do you think?"
Iterate based on feedback -- don't regenerate from scratch unless directed

Managing large batches

For projects generating many images (100+ iterations):

Use consistent filename_prefix for project/category grouping
Track promising seeds and prompts in a text file or project notes
Periodically clean exploration outputs -- keep only selected refinement/final images
Use ComfyUI's built-in image comparison to review batches side-by-side

Troubleshooting

Out of VRAM: Switch to flux-2-klein-4b or reduce resolution. Check your GPU's VRAM capacity and adjust model/resolution accordingly.
Slow generation: Use TAESD preview (VAE approximation) for fast previews during exploration. Full VAE for finals only.
Inconsistent style: Lock the model, sampler, and CFG. Only vary prompt and seed.
ComfyUI unreachable: Check that ComfyUI is running. curl ${COMFYUI_BASE_URL}/system_stats for health check.

concept-art