Vizualization on adjacent meshes with freefem

Hello all,

I have different velocity fields vk[ ] define on adjacent (non-overlapping) meshes ThK and on FE space VhK (each mesh shares one adjacent boundary edge with its neighbour)

How can I gather all these velocity fields, to plot them on the same figure with FreeFem ? What is the best strategy ?

I have tried to add all the meshes ThK to re-create the mesh TH and then interpolate the results on the global mesh TH :

//TH=sum(ThK)
fespace VH(TH, P1)
VH UG, uloc
// loop on index k //
matrix interpol = interpolate(VH, VhK, inside=1);
uloc[]= interpol*vk[];
UG[]=UG[]+uloc[];

But by doing this, the visualization is very bad and in some cases I can hardly see something.

Thank you,

Best regards,

Loïc,