3ds Max Data Exchange Interface (3DXI) and COLLADA

3ds Max Data Exchange Interface (3DXI)and COLLADA

Bernard LefebvreAUTODESK - Media and Entertainment

Dev. Tech. Support

Overview3DXI – High Level API for 3ds Max SDK

Goals and Targets Interface Scope Overview Flexibility and Customization

COLLADA - Digital Asset Exchange Schema Goals and Guidelines Library types

3DXI in COLLADA Export plug-in How things work together Data round-trip demonstration

3DXI - High Level APIfor 3ds Max SDK

3DXI (formerly known as IGame) was introduced as a set of interfaces for rapid data extraction

Dual target Allow novice 3ds Max developers to extract

data with minimal effort Allow for the gradual adoption of 3DXI within

existing pipelines

3DXI: Goals and Targets

M&E is devoting R&D resources to maintain and expand 3DXI Short term goal:

Complete the set of entities exposed when parsing the scene graph

Mid term goal: Incorporate import capabilities to the API

Long term goal: Become a standard API for data exchange in

and out of 3ds Max

3DXI: Goals and Targets

3DXI: Interface Scope Overview

Provides unified Scene traversal and Object enumeration

Well defined data containers for top level Nodes and Materials interfaces with list of their children

class IGameScene{virtual bool InitialiseIGame(bool selected = false)=0;

};


Built-in Conversion System Coordinate System Conversions (3ds

Max, OpenGL, DirectX, custom)

IGameConversionManager * cm = GetConversionManager();

cm->SetCoordSystem(IGameConversionManager::IGAME_D3D);

Access to 3ds Max elementsGeometry, Spline, Lights and Cameras, Helper

Objects

Modifiers, Skin Deformers, Materials, Textures (including Bitmap)

Controllers, Constraints, IK Chain, Bipeds

Object Parameter Containers Paramblocks, Custom Attributes, MXS plugins, Custom

Node Data



Mesh AccessAll Vertex Colors, Alpha, Illumination,

Normals, Texture Coordinates, Binormals, and Tangents are accessed directly

Vertex normals calculated based on the smoothing group of the face

Support for Mesh and MNMesh (N-sided polygons)


AnimationAccess to TCB, Euler Controllers,

Constraints and Biped systemsOption for key sampling for parametric

controllers


DirectX EffectsDirectX 9 Shader Material

supported directly via IGameMaterial


IGameFX – main interface to D3D effect, compliant with HLSL COLLADA FX (1.4.0)

IGameFXProperty – interface for individual parameter (property), can be extracted to general IGameProperty

IGameFXTechnique – interface for technique information

IGameFXPass – interface for pass information

IGameFXFunction – access to function’s data

3DXI: Interface Scope Overview Graphical Class Hierarchy

IExportEntity

IGameConstraint

IGameModifier

IGameObject

IGameMaterial

IGameTexture Map

IGameUVGen

IGameGenMod

IGameMorpher

IGameSkin

IGameGenObject

IGameLight

IGameCamera

IGameMesh

IGameIKChain

IGameSpline

IGameXRefObject

IGameSupportObject

IGameScene

IGameNode

IGameControl

IGameKey

IGameFX

FaceEx

IPropertyContainer

IGameConversionManager

IGameProperty

3DXI: Interface Scope OverviewCode Example: Simplification

Extracting key frame data from controller (3ds Max SDK):

Control * cont = node->GetTMController()->GetPositionController()if (!cont)

return;IKeyControl * ikc = GetKeyControlInterface(cont);// TCB point3if (ikc && (cont->ClassID()== Class_ID(TCBINTERP_POINT3_CLASS_ID, 0))){

for (int i=0; i<ikc->GetNumKeys(); i++) {ITCBPoint3Key key;ikc->GetKey(i, &key);// process data

}}

3DXI: Interface Scope OverviewCode Example: Simplification

The same data in 3DXI can be extracted as:

IGameKeyTab poskeys;IGameControl * gameControl = gameNode->GetIGameControl();

if (!gameControl) return; gameControl->GetTCBKeys(poskeys,IGAME_POS));// process data

3DXI: Flexibility and Customization

Ability to fit into existing pluginsAll the major 3DXI classes provide access to

the underlying 3ds Max object:

INode * node = gameNode->GetMaxNode();

Object * obj = gameObject->GetMaxObject();

Mesh * mesh = gameMesh->GetMaxMesh();

Mtl* mat = gameMaterial->GetMaxMaterial();

Conversion from INode* to IGameNode*:

IGameNode * gameNode = GetIGameInterface()->GetIGameNode(node);


Object properties are stored in different containers

IParamBlock, IParamBlock2, Custom Attributes, MXS plugins

3DXI collects all properties from different 3ds Max containers automatically


And provides an interface to extract them by index or by name (as the name known to MAXScript)

IGameObject * obj = gameNode->GetIGameObject();switch(obj->GetIGameType()){ case IGameObject::IGAME_LIGHT: { IGameLight * light = (IGameLight*)obj; IGameProperty * prop =

GetIPropertyContainer()->QueryProperty(_T("color")); Point3 pvalue; if (prop) // property can be NULL, if name not found

prop->GetPropertyValue(pvalue);

}}


If you use User Defined Properties: XML defined in IGameProp.xml

<ExportUserData><UserProperty><id>101</id><simplename>MyString</simplename><keyName>IGameTestString</keyName><type>string</type></UserProperty></ExportUserData>

Extract Custom Property

IGameObject * obj = gameNode->GetIGameObject();IGameSupportObject * hO = (IGameSupportObject*)obj;IPropertyContainer * cc = hO->GetIPropertyContainer();IGameProperty * prop = cc->QueryProperty(101);TCHAR * buf;if(prop)

prop->GetPropertyValue(buf);

3DXI: Flexibility and Customization Example of IGameProperty advantage

for lights: Omni - is paramblock based Skylight – is paramblock2 based Mr_Area_Omni – is scripted plugin

A single way to access property:

IGameProperty * prop =cc->QueryProperty(_T(“Multiplier"));

COLLADA-

Digital Asset Exchange Schema

COLLADA: Goals and Guidelines

COLLADA - An open Digital Asset Exchange (XML) Schema for the interactive 3D industry

Driven by Sony Computer Entertainment , Inc.

Current version is 1.4.0 https://collada.org http://www.khronos.org/

collada/

https://collada.org/

COLLADA: Goals and Guidelines COLLADA is not a game engine format Goals:

To liberate digital assets from proprietary binary formats into XML open-source format

No binary data within XML Shema Flexibility and Scalability

To provide a standard common format for digital content users

XML Schema, Specification, and API

To be a basis for common data exchange between 3D applications

User’s quote: “The days of game developers writing custom export plug-ins for modeling packages are, from what we've seen, over”

COLLADA 1.4New features.

COLLADA FX Cross-platform standard shader and effects

definition written in XML. Targets:

High-end systems running OpenGL Shading Language (GLSL) and Cg (HLSL coming),

Resource-constrained systems (OpenGL ES 1.x profile).

COLLADA Physics Rigid Body Dynamics, Rag Dolls, Contraints,

Collision Volumes. Enables data interchange between Ageia

(Novodex), Havok, Meqon, ODE and other game physics middleware

COLLADA: Library types library_animations, library_animation_clips library_geometries library_controllers library_nodes library_materials, library_images library_cameras, library_lights library_visual_scenes

library_effects

library_physics_models library_physics_materials, library_force_fields library_physics_scenes

COLLADA: Library typesExample of <animation> created by 3ds Max COLLADA exporter

<animation id="ColladaAnim.max_animation"> <animation id="Box01-Translate"> <source id="Box01-Translate-X-time"> <float_array id="Box01-Translate-X-time-array" count="2">0

3.333333</float_array> <technique_common> <accessor source="#Box01-Translate-X-time-array" count="2"> <param name="TIME" type="float"></param> </accessor> </technique_common> </source> <source id="Box01-Translate-X-value"> <float_array id="Box01-Translate-X-value-array" count="2">0

100.000000</float_array> <technique_common> <accessor source="#Box01-Translate-X-value-array" count="2"> <param name="TRANS.X" type="float"></param> </accessor> </technique_common> </source>

COLLADA: Library typesExample of <animation> (Continue)

<source id="Box01-Translate-X-interp"> <Name_array id="Box01-Translate-X-interp-array" count="2">BEZIER

BEZIER</Name_array> <technique_common> <accessor source="#Box01-Translate-X-interp-array" count="2"> <param

name="TRANS.X" type="Name"></param> </accessor> </technique_common></source><source id="Box01-Translate-X-intgt"> <float_array id="Box01-Translate-X-intgt-array" count="2">-0 -0</float_array> <technique_common> <accessor source="#Box01-Translate-X-intgt-array" count="2"> <param

name="TRANS.X" type="float"></param> </accessor> </technique_common></source><source id="Box01-Translate-X-outtgt"> <float_array id="Box01-Translate-X-outtgt-array" count="2">0 0</float_array> <technique_common> <accessor source="#Box01-Translate-X-outtgt-array" count="2"> <param name="TRANS.X" type="float"></param> </accessor> </technique_common></source>

COLLADA: Library types

Example of <animation> (Continue)

<sampler id="Box01-Translate-X-sampler"> <input semantic="INPUT"

source="#Box01-Translate-X-time"></input> <input semantic="OUTPUT"

source="#Box01-Translate-X-value"></input> <input semantic="INTERPOLATION" source="#Box01-Translate-X-

interp"></input> <input semantic="IN_TANGENT" source="#Box01-Translate-X-

intgt"></input> <input semantic="OUT_TANGENT" source="#Box01-Translate-X-

outtgt"></input> </sampler> <channel source="#Box01-Translate-X-sampler"

target="Box01/Trans.X"></channel> </animation> </animation>

COLLADA: Library typesExample of <mesh> element exported by 3ds Max COLLADA exporter

<geometry id="Box01-obj" name="Box01"> <mesh> <source id="Box01-obj-position"> <float_array id="Box01-obj-position-array" count="24">-15.000000 -15.000000 0 15.000000 -

15.000000 0 -15.000000 15.000000 0 15.000000 15.000000 0 -15.000000 -15.000000 30.000000 15.000000 -15.000000 30.000000 -15.000000 15.000000 30.000000 15.000000 15.000000 30.000000</float_array>

<technique_common> <accessor source="#Box01-obj-position-array" count="8" stride="3"> <param name="X" type="float"></param> <param name="Y" type="float"></param> <param name="Z" type="float"></param> </accessor> </technique_common> </source> <source id="Box01-obj-normal"> <float_array id="Box01-obj-normal-array" count="72">0 0 -1.000000 0 0 -1.000000 0 0 -

1.000000 0 0-1.000000 0 0 1.000000 0 0 1.000000 0 0 1.000000 0 0 1.000000 0 -1.000000 0 0 -1.000000 0 0 -1.000000 0 0 -1.000000 0 1.000000 0 0 1.000000 0 0 1.000000 0 0 1.000000 0 0 0 1.000000 0 0 1.000000 0 0 1.000000 0 0 1.000000 0 -1.000000 0 0 -1.000000 0 0 -1.000000 0 0 -1.000000 0 0</float_array>

<technique_common> <accessor source="#Box01-obj-normal-array" count="24" stride="3"> <param name="X" type="float"></param> <param name="Y" type="float"></param> <param name="Z" type="float"></param> </accessor> </technique_common> </source>

COLLADA: Library typesExample of <mesh> (Continue) <source id="Box01-obj-mapchan-1"> <float_array id="Box01-obj-mapchan-1-array" count="36">0 0 0 1.000000 0 0 0 1.000000

0 1.000000 1.000000 0 0 0 0 1.000000 0 0 0 1.000000 0 1.000000 1.000000 0 0 0 0 1.000000 0 0 0 1.000000 0 1.000000 1.000000 0</float_array>

<technique_common> <accessor source="#Box01-obj-mapchan-1-array" count="12" stride="3"> <param name="S" type="float"></param> <param name="T" type="float"></param> <param name="R" type="float"></param> </accessor> </technique_common> </source> <vertices id="Box01-obj-vertex"> <input semantic="POSITION" source="#Box01-obj-position"></input> </vertices> <polylist material="ColorMaterial_14782296" count="6"> <input semantic="VERTEX" source="#Box01-obj-vertex" offset="0"></input> <input semantic="NORMAL" source="#Box01-obj-normal" offset="1"></input> <input semantic="TEXCOORD" source="#Box01-obj-mapchan-1" offset="2"

set="1"></input> <vcount>4 4 4 4 4 4 </vcount> <p>0 0 0 2 1 2 3 2 3 1 3 1 4 4 4 5 5 5 7 6 7 6 7 6 0 8 8 1 9 9 5 10 11 4 11 10 1 12 12 3 13

13 7 14 15 5 15 14 3 16 16 2 17 17 6 18 19 7 19 18 2 20 20 0 21 21 4 22 23 6 23 22 </p> </polylist> </mesh></geometry>

COLLADA: external references.

<library_visual_scenes> <visual_scene id="Animation_max" name="Animation_max"> <node id="MyGeometry" sid="MyGeometry"

name="MyGeometry"> <translate sid="Trans">3.01744 7.61249 0 </translate> <rotate sid="RotZ">0 0 1 41.2879</rotate> <rotate sid="RotY">0 1 0 -32.6151</rotate> <rotate sid="RotX">1 0 0 -25.3289</rotate> <instance_geometry

url="./SourceGeometry.dae#MyGeometry-obj"> </instance_geometry>

</node> </visual_scene> </library_visual_scenes>

3DXI in COLLADA Export plug-in

3DXI for COLLADA M&E is fully

committed to COLLADA

COLLADA Exporter and Importer effort by Feeling Software, Inc. Personal thanks to Guillaume Laforte

3ds Max Exchange plugins for COLLADA support version 1.4.0

For 3ds Max 7 and 3ds Max 8.

3DXI for COLLADA 3DXI in action

All code snippets are taken from 3ds Max COLLADA exporter

//starting pointint ColladaExporter::DoExport(const TCHAR* name, ExpInterface* ei,

Interface* i, BOOL suppressPrompts, DWORD options){

IGameScene* pIgame = GetIGameInterface(); pIgame->InitialiseIGame(bool(options & SCENE_EXPORT_SELECTED));}

Entire scene traversal happening here All root nodes and materials (including their

children) are enumerated

3DXI for COLLADA 3DXI in action


//Create <material::effect> LibraryIGameMaterial* mat = pIgame->GetRootMaterial(i); //for all scene mtlsIGameFX* gameFX = mat->GetIGameFX();if(!gameFX) return; //not a DX Material

const TCHAR* fxFilename = gameFX->GetEffectFileName();

int np = gameFX->GetNumberOfProperties();for (int j = 0; j < np; j++){ IGameFXProperty* fxp = gameFX->GetIGameFXProperty(j); IGameProperty* property = fxp->GetIGameProperty(); // access to IGameProperty

if (fxp->GetPropertyUsage() == IGameFXProperty::IGAMEFX_LIGHT) IGameNode* lightNode = fxp->GetBindingNode(); // bound light node

}int nt = gameFX->GetNumberOfTechniques(), i = 0;do{ IGameFXTechnique* fxTechnique = gameFX->GetIGameFXTechnique(i); for (int j = 0; j < fxTechnique->GetNumberOfPasses(); j++) IGameFXPass* pass = fxTechnique->GetIGameFXPass(j);}while (++i < nt);

3DXI for COLLADA

3DXI in actionAll code snippets are taken from 3ds Max

COLLADA exporter

//extract Object dataIGameNode *node = pIgame->GetTopLevelNode(i); //for all scene nodesIGameObject* object = node->GetIGameObject();switch (object->GetIGameType()){ case IGameObject::IGAME_LIGHT: AddLightObject(node, object); break; case IGameObject::IGAME_CAMERA: AddCameraObject(node, object); break; case IGameObject::IGAME_MESH: AddMeshObject(node, object); break;}

Object properties are collected into IGamePropertyContainer at this point.

3DXI for COLLADA 3DXI in action – Access Mesh


//export MeshIGameObject* object = node->GetIGameObject();IGameMesh* mesh = (IGameMesh*) obj;mesh->InitializeData();// mesh vertex positionsfor (int i = 0; i < mesh->GetNumberOfVerts(); i++){

Point3 vert; mesh->GetVertex(i, vert, exporterOptions->ExportObjectSpace());

}// mesh normalsfor (int i = 0; i < mesh->GetNumberOfNormals(); i++){

Point3 n; mesh->GetNormal(i,n, exporterOptions->ExportObjectSpace());

}// mesh tangents and binormals for a channelint chan = 1;for (int i = 0; i < mesh->GetNumberOfTangents() ; i++){

Point3 t,b; t = mesh->GetTangent(i,chan); b = mesh->GetBinormal(i,chan);

}// mesh texture vertices for a channelfor (int i = 0; i < mesh->GetNumberOfMapVerts(chan); i++){

Point3 tv; mesh->GetMapVertex(chan, i, tv);

}

For mesh all data (vertices, normals, map channels, binrormals, etc) collected/calculated. FaceEx* structure is stored per face basis

3DXI for COLLADA

Data round-trip demonstration Mesh model textured, skinned with

animated biped as a rig

3DXI Resources

http://beta.discreet.com

http://sparks.autodesk.com

https://collada.org/public_forum

On the DVD:

3DXIHelp.chm (maxsdk\help)

3DXI Headers (maxsdk\include\IGame)

COLLADA Exporter and Importer (maxsdk\samples\Collada)

Questions ?

[email protected]

Documents

3ds Max Data Exchange Interface (3DXI) and COLLADA