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The MotionTrackerObject class represents a Cinema 4D motion tracker object. It provides read-only access to properties of the loaded video footage and the created 2D tracks.

MotionTrackerObject objects are an instance of Omotiontracker .

Access

A MotionTrackerObject object can be accessed like any other object.

// This example accesses the Motion Tracker object // to print the used footage filename to the console.

// check if an object is selected and if it is a Motion Tracker object BaseObject * const obj = doc-> GetActiveObject (); if (obj == nullptr || !obj-> IsInstanceOf ( Omotiontracker )) return maxon::IllegalArgumentError( MAXON_SOURCE_LOCATION );

const MotionTrackerObject * const moTrackObject = static_cast< MotionTrackerObject * > (obj);

MtFootageData * footage = moTrackObject-> GetFootageData (); if (footage == nullptr ) return maxon::UnexpectedError( MAXON_SOURCE_LOCATION ); const Filename footageName = footage-> GetFootageName (); ApplicationOutput ( "Footage: " + footageName. GetString ());

// do not forget to free the copy MtFootageData::Free (footage);

Allocation/Deallocation

MotionTrackerObject objects are created with the usual tools:

MotionTrackerObject::Alloc() : Creates a new MotionTrackerObject .
MotionTrackerObject::Free() : Deletes the given MotionTrackerObject .

// This example creates a new motion tracker object and adds it to the scene. MotionTrackerObject * const moTrackObj = MotionTrackerObject::Alloc (); if (moTrackObj == nullptr ) return maxon::OutOfMemoryError( MAXON_SOURCE_LOCATION ); moTrackObj-> SetName ( "New Motion Tracker" _s); doc-> InsertObject (moTrackObj, nullptr , nullptr );

参数

The standard object parameters of the Motion Tracker object can be accessed with C4DAtom::GetParameter() and C4DAtom::SetParameter() . The parameter IDs are defined in omotiontracker.h .

Additionally, footage information can be accessed with MotionTrackerObject::GetFootageData() (see below).

Access Data

Internal data of a MotionTrackerObject can be accessed by acquiring specialised data containers that store information on the footage and the 2D tracking data.

MotionTrackerObject::Get2dTrackData() ：返回 MtFootageData object that stores information on the footage.
MotionTrackerObject::GetFootageData() ：返回 Mt2dTrackData object that stores 2D track information.

见 MtFootageData Manual and Mt2dTrackData / Mt2dTrack / MtData Manual .

// This example accesses both footage data and track data // from the given MotionTrackerObject.

// access MtFootageData MtFootageData * footage = moTrackObject-> GetFootageData (); if (footage == nullptr ) return maxon::UnexpectedError( MAXON_SOURCE_LOCATION ); const Int32 firstFrame = footage-> GetFirstFrameNumber (); const Int32 lastFrame = footage-> GetLastFrameNumber (); const String firstFrameStr = String::IntToString (firstFrame); const String lastFrameStr = String::IntToString (lastFrame); ApplicationOutput ( "Footage Range: " + firstFrameStr + " - " + lastFrameStr);

// do not forget to free the copy MtFootageData::Free (footage);

// access Mt2dTrackData Mt2dTrackData * trackData = moTrackObject-> Get2dTrackData (); if (trackData == nullptr ) return maxon::UnexpectedError( MAXON_SOURCE_LOCATION ); const Int32 trackCount = trackData-> GetTrackCount (); ApplicationOutput ( "Track Count: " + String::IntToString (trackCount));