feat: add hermes-blender skill for 3D modeling and rendering

[kshitijk4poor]

Hermes-Blender Integration Skill

New skill for controlling a running Blender instance programmatically via the blender-mcp addon (2.2k stars, MIT licensed). Enables 3D modeling, materials, modifiers, animation, and rendering through Hermes.

Architecture

Hermes Agent -> Python socket (port 9876) -> Blender MCP Addon -> bpy Python API

The agent communicates with a running Blender instance via a TCP socket server created by the blender-mcp addon. Two methods:

1. Direct socket — blender_exec() pattern (like td_exec() in the TouchDesigner skill)
2. MCP tools — optional, configure uvx blender-mcp in Hermes config

What's included

File	Lines	Contents
SKILL.md	215	Setup, architecture, blender_exec/blender_cmd patterns, workflow, commands, object types
references/pitfalls.md	150	19 pitfalls from live testing on Blender 5.1.1
references/bpy-api.md	220	Essential bpy: objects, transforms, bmesh, materials, modifiers, camera, lighting, rendering, animation, collections
references/recipes.md	270	5 complete recipes: low-poly landscape, glass sphere, procedural donut, turntable animation, render-to-file

Total: 4 files, 855 lines

Tested live on Blender 5.1.1

• Installed addon via --python startup script (no manual GUI interaction needed)
• Verified socket connection, scene creation, material assignment, EEVEE rendering
• Discovered and documented Blender 5.x-specific pitfalls:
  • execute_code result is always empty (eval not captured) — pitfall Fix VM instance sharing across tasks #6
  • EEVEE engine name is 'BLENDER_EEVEE' not 'BLENDER_EEVEE_NEXT' — pitfall Rl capabilities && File Operator Tools #15
  • Render timeouts need 120s+ for Cycles; EEVEE ~17s at 720p

Key design decisions

• Uses existing blender-mcp addon rather than building a custom handler — the addon is battle-tested (2.2k stars), supports PolyHaven asset integration and Hyper3D AI model generation
• Direct socket pattern as primary communication (not MCP subprocess) — more reliable, same pattern as the TouchDesigner skill
• Discovery-friendly — the skill documents how to query available engines, objects, and materials rather than hardcoding names that change between Blender versions

Related

• Companion to PR feat: add TouchDesigner integration skill (twozero MCP) #10081 (TouchDesigner skill) — same architecture pattern
• Replaces the previously merged-then-removed blender-mcp skill from PR feat(skills): add blender-mcp optional skill for 3D modeling #1531

[kshitijk4poor]

Closing in favor of updating the existing blender-mcp optional skill in-place with this richer content. New PR incoming.