Path with orientation from points

[arzezniczak]

I have simple path data from some application - just list of xyz coordinates:

(0, 0, 0)
(100, 0, 50)
(100, 100, 100)
(0, 100, 50)
(0, 0, 0)

I want to use this data to create Unigine::Path and then use this path in Unigine::WorldTransformPath to animate object - transform it along this path.
I'm adding this points to Unigine::Path using setFramePosition and setFrameTime.

I saw that Unigine::WorldTransformPath have method setOrientation that should keep my object correctly oriented during transformation animation along path, but it seems like it's not working for me - object is always oriented in one direction.

How can I correct object orientation? Do I need to somehow calculate rotation in every path frame (setFrameRotation) and this will be used to object orientation?

[morbid]

Hello,

Could you please provide a code sample?

Thanks.

[arzezniczak]

Unigine::Vector<Unigine::Math::vec3> points;
//...adding a lot of vec3 from my other app

Unigine::PathPtr path = Unigine::Path::create( );
for ( int pI = 0; pI < points.size( ); ++pI )
{
  const int frame = path->addFrame( );
  path->setFramePosition( frame, points[pI] );
  path->setFrameTime( frame, 1.0 * (float)pI );
}

Unigine::String pathFile = "myPath.path";
path->save( pathFile );

Unigine::NodeReferencePtr fbxReference = Unigine::NodeReference::create( "myFbx.fbx" );
  
Unigine::WorldTransformPathPtr worldTransformPath = Unigine::WorldTransformPath::create( pathFile );
worldTransformPath->setLoop( 1 );
worldTransformPath->setOrientation( 1 );
worldTransformPath->setRadius( 100 );
worldTransformPath->addChild( fbxReference->getNode( ) );
worldTransformPath->play( );
worldTransformPath->release( );
Unigine::Editor::get( )->addNode( worldTransformPath->getNode( ) );

I'm currently using Unigine 2.7.2.1.

[moroz]

Hi!

The Orientation parameter has default value 1.

If it's settled to 1, the transformation of intermediate frame between two frames is calculated via full matrices from these frames.

If == 0, only the position from frames is taken for an intermediate frame, scale and rotation are taken from node transformation.

You should use setFrameRotation or setFrameTransform for each frame.

[arzezniczak]

Hello,
Do you have any hints for how to calculate this transformations having only list of vec3 coordinates?

[moroz]

Use vector between two points as Axis for basis.

Example. Don't forget calculate special case when axis_y and Vec3::UP are collinear.

Vec3 start_p, end_p;
auto axis_y = (end_p - start_p).normalize();
auto axis_z (Vec3::UP);
auto axis_x (cross(axis_y, axis_z));
Mat4 transform(axis_x, axis_y, axis_z, start_p);