.dat (or any other data output) for multigrid3d mesh

I successfully implemented a multigrid refinement for a 3-D case. I want to output my refined meshes and velocities together in .dat (or .vtk) file format, to see them in a “Fluent” kind of environment! Is there a format? I understand that svgwriter2D is specific to 2D case and it takes MultiGridManagement2D as input, is there any 3D version?

Dear manas,
I’m trying to implement a 3D multigrid case. But I’m puzzled in implementing different bc at different faces. Would you apply some of your experiences?

void applyOuterBoundaryConditions( MultiGridLattice3D<T,DESCRIPTOR>& lattice,
ConvectiveRefinementParameters const& parameters,
OnLatticeBoundaryCondition3D<T,DESCRIPTOR>& bc)
Box3D coarsestBoundingBox=lattice.getComponent(0).getBoundingBox();
for (plint iLevel = 0; iLevel < lattice.getNumLevels(); ++iLevel) {

    MultiBlockLattice3D<T,DESCRIPTOR>& oneLattice = lattice.getComponent(iLevel);


    Box3D boundingBox = coarsestBoundingBox.multiply(util::intTwoToThePower(iLevel));
    Box3D box = boundingBox; 

    Box3D inlet   (box.x0,   box.x0,   box.y0,   box.y1,   box.z0+1, box.z1);
    Box3D outlet  (box.x1,   box.x1,   box.y0,   box.y1,   box.z0+1, box.z1);
    Box3D yBottom (box.x0+1, box.x1-1, box.y0,   box.y0,   box.z0+1, box.z1-1);
    Box3D yTop    (box.x0+1, box.x1-1, box.y1,   box.y1,   box.z0+1, box.z1-1);
    Box3D zBottom (box.x0,   box.x1,   box.y0,   box.y1,   box.z0,   box.z0);
    Box3D zTop    (box.x0+1, box.x1-1, box.y0,   box.y1,   box.z1,   box.z1);

    // Inlet boundary condition.		
    bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, inlet, boundary::dirichlet);

    // Outlet boundary condition.
	bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, outlet, boundary::outflow);

    // Lateral boundary conditions.
    bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, yBottom, boundary::dirichlet);      
    bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, yTop, boundary::dirichlet);       
     bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, zBottom, boundary::dirichlet);      
    bc.setVelocityConditionOnBlockBoundaries(oneLattice, boundingBox, zTop, boundary::freeslip);

//Initial Velocity & Density
setBoundaryVelocity( lattice.getComponent(iLevel), 
     lattice.getComponent(iLevel).getBoundingBox(), Array<T,3>((T)0.,(T)0.,(T)0.) );		
initializeAtEquilibrium( lattice.getComponent(iLevel), lattice.getComponent(iLevel).getBoundingBox(), InletVelocity<T>(parameters[iLevel]) );


I know that to the coarsest grid I can set the different edges boundary by telling the x0,x1,y0,y1,z0,z1. But I've no idea how to deal with the fine girds. 

By the way, do you know how to write the original multigridlattice3d and multigridstensorfields3d to VTK files?

Thank you so much.