Chapter 4.2: 3D Models (.p3d)

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Einführung

Every physical object in DayZ -- weapons, clothing, buildings, vehicles, trees, rocks -- is a 3D model stored in Bohemia's proprietary P3D format. The P3D format is far more than a mesh container: it encodes multiple levels of detail, collision geometry, animation selections, memory points for attachments and effects, and proxy positions for mountable items. Understanding how P3D files work and how to create them with Object Builder is essential for any mod that adds physical items to the game world.

This chapter covers the P3D format structure, the LOD system, named selections, memory points, the proxy system, animation configuration via model.cfg, and the import workflow from standard 3D formats.

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Inhaltsverzeichnis

• P3D Format Overview
• Object Builder
• The LOD System
• Named Selections
• Memory Points
• The Proxy System
• Model.cfg for Animations
• Importing from FBX/OBJ
• Common Model Types
• Common Mistakes
• Best Practices

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P3D Format Overview

P3D (Point 3D) is Bohemia Interactive's binary 3D model format, inherited from the Real Virtuality engine and carried forward into Enfusion. It is a compiled, engine-ready format -- you do not write P3D files by hand.

Key Characteristics

• Binary format: Not human-readable. Created and edited exclusively with Object Builder.
• Multi-LOD container: A single P3D file contains multiple LOD (Level of Detail) meshes, each with a different purpose.
• Engine-native: The DayZ engine loads P3D directly. No runtime conversion occurs.
• Binarized vs. unbinarized: Source P3D files from Object Builder are "MLOD" (editable). Binarize converts them to "ODOL" (optimized, read-only). The game can load both, but ODOL loads faster and is smaller.

File Types You Will Encounter

Extension	Description
.p3d	3D model (both MLOD source and ODOL binarized)
.rtm	Runtime Motion -- animation keyframe data
.bisurf	Surface properties file (used alongside P3D)

MLOD vs. ODOL

Property	MLOD (Source)	ODOL (Binarized)
Created by	Object Builder	Binarize
Editable	Yes	No
File size	Larger	Smaller
Load speed	Slower	Faster
Used during	Development	Release
Contains	Full edit data, named selections	Optimized mesh data

Important: When you pack a PBO with binarization enabled, your MLOD P3D files are automatically converted to ODOL. If you pack with -packonly, the MLOD files are included as-is. Both work in-game, but ODOL is preferred for release builds.

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Object Builder

Object Builder is the Bohemia-provided tool for creating and editing P3D models. It is included in the DayZ Tools suite on Steam.

Core Capabilities

• Create and edit 3D meshes with vertices, edges, and faces.
• Define multiple LODs within a single P3D file.
• Assign named selections (groups of vertices/faces) for animation and texture control.
• Place memory points for attachment positions, particle origins, and sound sources.
• Add proxy objects for attachable items (magazines, optics, etc.).
• Assign materials (.rvmat) and textures (.paa) to faces.
• Import meshes from FBX, OBJ, and 3DS formats.
• Export validated P3D files for Binarize.

Workspace Setup

Object Builder requires the P: drive (workdrive) to be set up. This virtual drive provides a unified path prefix that the engine uses to locate assets.

P:\
  DZ\                        <-- Vanilla DayZ data (extracted)
  DayZ Tools\                <-- Tools installation
  MyMod\                     <-- Your mod's source directory
    data\
      models\
        my_item.p3d
      textures\
        my_item_co.paa

All paths in P3D files and materials are relative to the P: drive root. For example, a material reference inside the model would be MyMod\data\textures\my_item_co.paa.

Basic Workflow in Object Builder

1. Create or import your mesh geometry.
2. Define LODs -- at minimum, create Resolution, Geometry, and Fire Geometry LODs.
3. Assign materials to faces in the Resolution LOD.
4. Name selections for any parts that animate, swap textures, or need code interaction.
5. Place memory points for attachments, muzzle flash positions, ejection ports, etc.
6. Add proxies for items that can be attached (optics, magazines, suppressors).
7. Validate using Object Builder's built-in validation (Structure --> Validate).
8. Save as P3D.
9. Build via Binarize or AddonBuilder.

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The LOD System

A P3D file contains multiple LODs (Levels of Detail), each serving a specific purpose. The engine selects which LOD to use based on the situation -- distance from camera, physics calculations, shadow rendering, etc.

LOD Types

LOD	Resolution Value	Purpose
Resolution 0	1.000	Highest detail visual mesh. Rendered when the object is close to the camera.
Resolution 1	1.100	Medium detail. Rendered at moderate distance.
Resolution 2	1.200	Low detail. Rendered at far distance.
Resolution 3+	1.300+	Additional distance LODs.
View Geometry	Special	Determines what blocks the player's view (first person). Simplified mesh.
Fire Geometry	Special	Collision for bullets and projectiles. Must be convex or composed of convex parts.
Geometry	Special	Physics collision. Used for movement collision, gravity, placement. Must be convex or composed of convex decomposition.
Shadow 0	Special	Shadow casting mesh (close range).
Shadow 1000	Special	Shadow casting mesh (far range). Simpler than Shadow 0.
Memory	Special	Contains only named points (no visible geometry). Used for attachment positions, sound origins, etc.
Roadway	Special	Defines walkable surfaces on objects (vehicles, buildings with enterable interiors).
Paths	Special	AI pathfinding hints for buildings.

LOD Resolution Values (Visual LODs)

The engine uses a formula based on distance and object size to determine which visual LOD to render:

LOD selected = (distance_to_object * LOD_factor) / object_bounding_sphere_radius

Lower values = closer camera. The engine finds the LOD whose resolution value is the closest match to the calculated value.

Creating LODs in Object Builder

1. File --> New LOD or right-click the LOD list.
2. Select the LOD type from the dropdown.
3. For visual LODs (Resolution), enter the resolution value.
4. Model the geometry for that LOD.

LOD Requirements by Item Type

Item Type	Required LODs	Recommended Additional LODs
Handheld item	Resolution 0, Geometry, Fire Geometry, Memory	Shadow 0, Resolution 1
Clothing	Resolution 0, Geometry, Fire Geometry, Memory	Shadow 0, Resolution 1, Resolution 2
Weapon	Resolution 0, Geometry, Fire Geometry, View Geometry, Memory	Shadow 0, Resolution 1, Resolution 2
Building	Resolution 0, Geometry, Fire Geometry, View Geometry, Memory	Shadow 0, Shadow 1000, Roadway, Paths
Vehicle	Resolution 0, Geometry, Fire Geometry, View Geometry, Memory	Shadow 0, Roadway, Resolution 1+

Geometry LOD Rules

The Geometry and Fire Geometry LODs have strict requirements:

• Must be convex or composed of multiple convex components. The engine's physics system requires convex collision shapes.
• Named selections must match those in the Resolution LOD (for animated parts).
• Mass must be defined. Select all vertices in the Geometry LOD and assign mass via Structure --> Mass. This determines the object's physical weight.
• Keep it simple. Fewer triangles = better physics performance. A weapon's geometry LOD might have 20-50 triangles vs. thousands in the visual LOD.

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Named Selections

Named selections are groups of vertices, edges, or faces within a LOD that are tagged with a name. They serve as handles that the engine and scripts use to manipulate parts of a model.

What Named Selections Do

Purpose	Example Selection Name	Used By
Animation	bolt, trigger, magazine	model.cfg animation sources
Texture swaps	camo, camo1, body	hiddenSelections[] in config.cpp
Damage textures	zbytek	Engine damage system, material swaps
Attachment points	magazine, optics, suppressor	Proxy and attachment system

hiddenSelections (Texture Swaps)

The most common use of named selections for modders is hiddenSelections -- the ability to swap textures at runtime via config.cpp.

In the P3D model (Resolution LOD):

1. Select the faces that should be retexturable.
2. Name the selection (e.g., camo).

In config.cpp:

class MyRifle: Rifle_Base
{
    hiddenSelections[] = {"camo"};
    hiddenSelectionsTextures[] = {"MyMod\data\my_rifle_co.paa"};
    hiddenSelectionsMaterials[] = {"MyMod\data\my_rifle.rvmat"};
};

This allows different variants of the same model with different textures without duplicating the P3D file.

Creating Named Selections

In Object Builder:

1. Select the vertices or faces you want to group.
2. Go to Structure --> Named Selections (or press Ctrl+N).
3. Click New, enter the selection name.
4. Click Assign to tag the selected geometry with that name.

Tip: Selection names are case-sensitive. Camo and camo are different selections. Convention is lowercase.

Selections Across LODs

Named selections must be consistent across LODs for animations to work:

• If the bolt selection exists in Resolution 0, it must also exist in Geometry and Fire Geometry LODs (covering the corresponding collision geometry).
• Shadow LODs should also have the selection if the animated part should cast correct shadows.

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Memory Points

Memory points are named positions defined in the Memory LOD. They have no visual representation in-game -- they define spatial coordinates that the engine and scripts reference for positioning effects, attachments, sounds, and more.

Common Memory Points

Point Name	Purpose
usti hlavne	Muzzle position (where bullets originate, muzzle flash appears)
konec hlavne	End of barrel (used with usti hlavne to define barrel direction)
nabojnicestart	Ejection port start (where shell casings emerge)
nabojniceend	Ejection port end (direction of ejection)
handguard	Handguard attachment point
magazine	Magazine well position
optics	Optic rail position
suppressor	Suppressor mount position
trigger	Trigger position (for hand IK)
pistolgrip	Pistol grip position (for hand IK)
lefthand	Left hand grip position
righthand	Right hand grip position
eye	Eye position (for first-person view alignment)
pilot	Driver/pilot seat position (vehicles)
light_l / light_r	Left/right headlight positions (vehicles)

Directional Memory Points

Many effects need both a position and a direction. This is achieved with paired memory points:

usti hlavne  ------>  konec hlavne
(muzzle start)        (muzzle end)

The direction vector is: konec hlavne - usti hlavne

Creating Memory Points in Object Builder

1. Switch to the Memory LOD in the LOD list.
2. Create a vertex at the desired position.
3. Name it via Structure --> Named Selections: create a selection with the point name and assign the single vertex to it.

Note: The Memory LOD should contain ONLY named points (individual vertices). Do not create faces or edges in the Memory LOD.

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The Proxy System

Proxies define positions where other P3D models can be attached. When you see a magazine inserted in a weapon, an optic mounted on a rail, or a suppressor screwed onto a barrel -- those are proxy-attached models.

How Proxies Work

A proxy is a special reference placed in the Resolution LOD that points to another P3D file. The engine renders the proxy's referenced model at the proxy's position and orientation.

Proxy Naming Convention

Proxy names follow the pattern: proxy:\path\to\model.p3d

For attachment proxies on weapons, the standard names are:

Proxy Path	Attachment Type
proxy:\dz\weapons\attachments\magazine\mag_placeholder.p3d	Magazine slot
proxy:\dz\weapons\attachments\optics\optic_placeholder.p3d	Optics rail
proxy:\dz\weapons\attachments\suppressor\sup_placeholder.p3d	Suppressor mount
proxy:\dz\weapons\attachments\handguard\handguard_placeholder.p3d	Handguard slot
proxy:\dz\weapons\attachments\stock\stock_placeholder.p3d	Stock/buttstock slot

Adding Proxies in Object Builder

1. In the Resolution LOD, position the 3D cursor where the attachment should appear.
2. Go to Structure --> Proxy --> Create.
3. Enter the proxy path (e.g., dz\weapons\attachments\magazine\mag_placeholder.p3d).
4. The proxy appears as a small arrow indicating position and orientation.
5. Rotate and position the proxy to align correctly with the attachment geometry.

Proxy Index

Each proxy has an index number (starting from 1). When a model has multiple proxies of the same type, the index differentiates them. The index is referenced in config.cpp:

class MyWeapon: Rifle_Base
{
    class Attachments
    {
        class magazine
        {
            type = "magazine";
            proxy = "proxy:\dz\weapons\attachments\magazine\mag_placeholder.p3d";
            proxyIndex = 1;
        };
    };
};

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Model.cfg for Animations

The model.cfg file defines animations for P3D models. It maps animation sources (driven by game logic) to transformations on named selections.

Basic Structure

class CfgModels
{
    class Default
    {
        sectionsInherit = "";
        sections[] = {};
        skeletonName = "";
    };

    class MyRifle: Default
    {
        skeletonName = "MyRifle_skeleton";
        sections[] = {"camo"};

        class Animations
        {
            class bolt_move
            {
                type = "translation";
                source = "reload";        // Engine animation source
                selection = "bolt";       // Named selection in P3D
                axis = "bolt_axis";       // Axis memory point pair
                memory = 1;               // Axis defined in Memory LOD
                minValue = 0;
                maxValue = 1;
                offset0 = 0;
                offset1 = 0.05;           // 5cm translation
            };

            class trigger_move
            {
                type = "rotation";
                source = "trigger";
                selection = "trigger";
                axis = "trigger_axis";
                memory = 1;
                minValue = 0;
                maxValue = 1;
                angle0 = 0;
                angle1 = -0.4;            // Radians
            };
        };
    };
};

class CfgSkeletons
{
    class Default
    {
        isDiscrete = 0;
        skeletonInherit = "";
        skeletonBones[] = {};
    };

    class MyRifle_skeleton: Default
    {
        skeletonBones[] =
        {
            "bolt", "",          // "bone_name", "parent_bone" ("" = root)
            "trigger", "",
            "magazine", ""
        };
    };
};

Animation Types

Type	Keyword	Movement	Controlled By
Translation	translation	Linear movement along an axis	offset0 / offset1 (meters)
Rotation	rotation	Rotation around an axis	angle0 / angle1 (radians)
RotationX/Y/Z	rotationX	Rotation around a fixed world axis	angle0 / angle1
Hide	hide	Show/hide a selection	hideValue threshold

Animation Sources

Animation sources are engine-provided values that drive animations:

Source	Range	Description
reload	0-1	Weapon reload phase
trigger	0-1	Trigger pull
zeroing	0-N	Weapon zeroing setting
isFlipped	0-1	Iron sight flip state
door	0-1	Door open/close
rpm	0-N	Vehicle engine RPM
speed	0-N	Vehicle speed
fuel	0-1	Vehicle fuel level
damper	0-1	Vehicle suspension

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Importing from FBX/OBJ

Most modders create 3D models in external tools (Blender, 3ds Max, Maya) and import them into Object Builder.

Supported Import Formats

Format	Extension	Notes
FBX	.fbx	Best compatibility. Export as FBX 2013 or later (binary).
OBJ	.obj	Wavefront OBJ. Simple mesh data only (no animations).
3DS	.3ds	Legacy 3ds Max format. Limited to 65K vertices per mesh.

Import Workflow

Step 1: Prepare in your 3D software

• Model should be centered at origin.
• Apply all transforms (location, rotation, scale).
• Scale: 1 unit = 1 meter. DayZ uses meters.
• Triangulate the mesh (Object Builder works with triangles).
• UV unwrap the model.
• Export as FBX (binary, no animation, Y-up or Z-up -- Object Builder handles both).

Step 2: Import into Object Builder

1. Open Object Builder.
2. File --> Import --> FBX (or OBJ/3DS).
3. Review the import settings:
   • Scale factor (should be 1.0 if your source is in meters).
   • Axis conversion (Z-up to Y-up if needed).
4. The mesh appears in a new Resolution LOD.

Step 3: Post-import setup

1. Assign materials to faces (select faces, right-click --> Face Properties).
2. Create additional LODs (Geometry, Fire Geometry, Memory, Shadow).
3. Simplify geometry for collision LODs (remove small details, ensure convexity).
4. Add named selections, memory points, and proxies.
5. Validate and save.

Blender-Specific Tips

• Use the Blender DayZ Toolbox community addon if available -- it streamlines export settings.
• Export with: Apply Modifiers, Triangulate Faces, Apply Scale.
• Set Forward: -Z Forward, Up: Y Up in the FBX export dialog.
• Name mesh objects in Blender to match intended named selections -- some importers preserve object names.

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Common Model Types

Weapons

Weapons are the most complex P3D models, requiring:

• High-poly Resolution LOD (5,000-20,000 triangles)
• Multiple named selections (bolt, trigger, magazine, camo, etc.)
• Full memory point set (muzzle, ejection, grip positions)
• Multiple proxies (magazine, optics, suppressor, handguard, stock)
• Skeleton and animations in model.cfg
• View Geometry for first-person obstruction

Clothing

Clothing models are rigged to the character skeleton:

• Resolution LOD follows the character's bone structure
• Named selections for texture variants (camo, camo1)
• Simpler collision geometry
• No proxies (usually)
• hiddenSelections for color/camo variants

Buildings

Buildings have unique requirements:

• Large, detailed Resolution LODs
• Roadway LOD for walkable surfaces (floors, stairs)
• Paths LOD for AI navigation
• View Geometry to prevent seeing through walls
• Multiple Shadow LODs for performance at different distances
• Named selections for doors and windows that open

Vehicles

Vehicles combine many systems:

• Detailed Resolution LOD with animated parts (wheels, doors, hood)
• Complex skeleton with many bones
• Roadway LOD for passengers standing in truck beds
• Memory points for lights, exhaust, driver position, passenger seats
• Multiple proxies for attachments (wheels, doors)

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Häufige Fehler

1. Missing Geometry LOD

Symptom: Object has no collision. Players and bullets pass through it. Fix: Create a Geometry LOD with a simplified convex mesh. Assign mass to vertices.

2. Non-Convex Collision Shapes

Symptom: Physics glitches, objects bouncing erratically, items falling through surfaces. Fix: Break complex shapes into multiple convex components in the Geometry LOD. Each component must be a closed convex solid.

3. Inconsistent Named Selections

Symptom: Animations only work visually but not for collision, or shadow does not animate. Fix: Ensure every named selection that exists in the Resolution LOD also exists in Geometry, Fire Geometry, and Shadow LODs.

4. Wrong Scale

Symptom: Object is gigantic or microscopic in-game. Fix: Verify your 3D software uses meters as the unit. A DayZ character is approximately 1.8 meters tall.

5. Missing Memory Points

Symptom: Muzzle flash appears at the wrong position, attachments float in space. Fix: Create the Memory LOD and add all required named points at correct positions.

6. No Mass Defined

Symptom: Object cannot be picked up, or physics interactions behave strangely. Fix: Select all vertices in the Geometry LOD and assign mass via Structure --> Mass.

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Best Practices

1. Start with the Geometry LOD. Block out your collision shape first, then build the visual detail on top. This prevents the common mistake of creating a beautiful model that cannot collide properly.

2. Use reference models. Extract vanilla P3D files from the game data and study them in Object Builder. They show exactly what the engine expects for each item type.

3. Validate frequently. Use Object Builder's Structure --> Validate after every significant change. Fix warnings before they become mysterious in-game bugs.

4. Keep LOD triangle counts proportional. Resolution 0 might have 10,000 triangles; Resolution 1 should have ~5,000; Geometry should have ~100-500. Dramatic reduction at each level.

5. Name selections descriptively. Use bolt_carrier instead of sel01. Your future self (and other modders) will thank you.

6. Test with file patching first. Load your unbinarized P3D via file patching mode before committing to a full PBO build. This catches most issues faster.

7. Document memory points. Keep a reference image or text file listing all memory points and their intended positions. Complex weapons can have 20+ points.

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