3dsmax MCP

3ds Max MCP — Agent Guide

Principles:

• Match the user's request. Do not run setup, discovery, or scene analysis by habit.
• Do not call get_bridge_status or get_session_context as a session preamble.
• Prefer a dedicated MCP tool over raw MAXScript when a tool clearly matches the task.
• Do not render unless the user explicitly asks. Viewport capture is fine when visual proof is useful.
• Multiple Max instances: use MCP Claim This Max in the target window so tools hit the right session.

Tool Choice

Scene reads — use query_scene(action=...):

• overview | filter | class | property | selection | delta
• get_instances / get_dependencies — instancing and reference graph
• get_session_context — bridge + capabilities + overview + selection (on demand only)

Object/material/plugin inspection:

• inspect_object, inspect_properties, get_material_slots, get_materials
• analyze_node_orientation — pivot, bbox, local axes, world matrix before rig/vehicle/camera transforms
• introspect_class, introspect_instance, introspect_osl, discover_plugin_classes, map_class_relationships — unfamiliar plugin APIs and exact param names
• Arnold materials such as ai_standard_surface may not appear in class discovery; inspect with inspect_plugin_class or introspect_osl

Mutation:

• Use object, modifier, material, controller, organization, and viewport tools when they match.
• Verify after meaningful edits with query_scene(action=delta), re-inspection, or viewport capture.

Debugging:

• walk_references — trace dependencies from a live object
• watch_scene — track user actions during an interactive session
• execute_maxscript — fallback only when no dedicated tool exists

Scene Organization

Layers — manage_layers:

• Actions: list, create, delete, set_current, set_properties, add_objects, select_objects
• Properties: hidden, frozen, renderable, color, boxMode, castShadows, rcvShadows, xRayMtl, backCull, rename, parent

Groups — manage_groups:

• Actions: list, create, ungroup, open, close, attach, detach

Named Selection Sets — manage_selection_sets:

• Actions: list, create, delete, select, replace

Tool Reference

Scene reads

query_scene get_hierarchy get_instances get_dependencies

Objects

get_object_properties analyze_node_orientation set_object_property create_object delete_objects transform_object select_objects set_visibility clone_objects set_parent batch_rename_objects

Modifiers

add_modifier remove_modifier set_modifier_state set_modifier_property collapse_modifier_stack make_modifier_unique

Materials

• Create + assign: assign_material, create_material_from_textures, smart_import, palette_laydown
• Edit: set_material_property, set_material_properties
• Inspect: get_material_slots, get_materials
• Multi/Sub: set_sub_material
• Textures: create_texture_map, set_texture_map_properties
• Dual pipeline: create_shell_material, replace_material, batch_replace_materials
• OSL: write_osl_shader

Material notes

• create_material_from_textures and smart_import default to OpenPBR. Pass material_class for Physical, Arnold, Redshift, V-Ray, MaterialX, Octane, etc. (see tool tripback hint.renderers).
• create_shell_material wraps two scene materials in Shell_Material (render slot 0, export/viewport slot 1), or builds from texture_folder with render_material_class / export_material_class. Shell is a container, not a renderer.

Viewport

• Fast: capture_viewport
• Multi-angle grid: capture_multi_view
• Fullscreen: capture_screen (requires enabled=True)

External .max files (no scene load)

• inspect_max_file, search_max_files, merge_from_file, batch_file_info

Plugin discovery

• discover_plugin_surface, get_plugin_manifest, refresh_plugin_manifest
• inspect_plugin_class, inspect_plugin_constructor, inspect_plugin_instance
• MCP resources: resource://3dsmax-mcp/plugins/{name}/manifest|guide|recipes|gotchas

tyFlow

• Create: create_tyflow, create_tyflow_preset
• Inspect: get_tyflow_info (include_operator_properties for deep readback)
• Edit: modify_tyflow_operator, set_tyflow_shape, set_tyflow_physx, add_tyflow_collision
• Simulate: reset_tyflow_simulation, get_tyflow_particle_count, get_tyflow_particles

Forest Pack

• scatter_forest_pack — surfaces + source geometry; auto footprint per variant

Controllers & wiring

• assign_controller, inspect_controller, inspect_track_view, set_controller_props, add_controller_target
• list_wireable_params, wire_params, get_wired_params, unwire_params

Data Channel

• add_data_channel, inspect_data_channel, set_data_channel_operator, add_dc_script_operator

Scene management

• manage_scene (hold/fetch/reset/save/info)
• get_state_sets, get_camera_sequence

When to Use execute_maxscript

Almost never. Only when there is genuinely no dedicated tool:

• Animation keyframing, render/environment settings, custom one-off scripted operations

Do not use for: anything a dedicated tool already does — properties, objects, materials, selection, batch ops, inspection.

MCP Tool Pitfalls

• set_modifier_property: name + modifier_index (1-based) for one modifier; modifier_class + names for batch. Inspect with inspect_properties(target="modifier") first.
• smart_import: default lod_filter="lod0". Shared maps match on asset id; variant meshes in a bundle folder with Textures/ share one material key — omit name_pattern for all variants.
• palette_laydown: sample_mode="random_per_subfolder" for large per-subfolder asset libraries; overflow_mode="palette_then_library" when more than 24 picks.
• scatter_forest_pack: needs non-zero widthlist/heightlist per geometry item. Hide source meshes after scatter.
• add_data_channel: reuses first DC modifier by default; create_new=true for a second stack entry.
• get_material_slots: prefer slot_scope="map" unless you need every param (slot_scope="all" + include_values:true is huge on Arnold/Physical).
• create_object: default pos_mode="ground" — pos is bottom-center contact, not bbox center. Tripback includes bbox, placement, groundContact.
• Box: width=X, length=Y, height=Z.
• list_wireable_params paths include [#Parameters] levels — pass through to wire_params as-is.
• create_shell_material: mcp_findMaterialByName uses sceneMaterials — getClassInstances Material is invalid (Material is not a MAXClass).
• python -m src.server runs as __main__; alias it to src.server before importing tool modules or from ..server import mcp creates a second empty FastMCP instance.

MAXScript Pitfalls

• No parens with keyword args: Box width:10 not Box() width:10
• Wrap in try/catch: try (...) catch (ex) (ex)
• Noise vs Noisemodifier: texture map vs modifier
• (getDir #temp) is Max temp, not OS temp
• .NET strings: convert to MAXScript strings before string methods
• Controller/wire paths: normalize display tokens like [#Z Position] to [#z_position]
• TCP fallback is opt-in; prefer the native bridge, and if Max viewport interaction stutters while fallback is running, stop the fallback and use the native bridge path.

OSL

• Use write_osl_shader for file I/O and compilation
• Use introspect_osl before wiring — not introspect_class on OSLMap (massive output)
• Shader function name must match shader_name; use unique names (cache reuse)
• OSLMap lowercases param names

MAXScript Reference (bundled)

Read the relevant reference file before writing unfamiliar MAXScript:

Unwrap UVW

• Open the editor: $Box001.modifiers[#Unwrap_UVW].edit() — not the OpenUnwrapUI macro alone

Standalone Chat (WIP)

Experimental in-Max chat (Customize UI → MCP → MCP Chat). Prefer external MCP for production.

• Same tools and safe_mode as external MCP
• Call query_scene / inspect_object for scene state — not auto-injected by default
• Slash commands: /reload, /clear, /help

Source: cl0nazepamm/3dsmax-mcp — distributed by TomeVault.