Problem : Character fbx export has weird animation becaus of IK I made a character in blender and add few actions to that. Also i used IK for legs and every thing is okay in blender viewport and animations work well. But when i export it as *fbx , it’s legs becomes weird.
I cant understand what the problem is because I previously made character with IK for legs and it works well as *fbx. because In that succesfull case i added IK influences as keyframes. Also in that case i animate copy rotation influences for legs. But now for this case they doesn’t work.
I’ve tried a lot of solutions such as apply transform , bake animation. But none of them work and character always have weird legs.
here , what we see in blender :

and these are what we see in exprted *fbx :
Thanks my merciful God ! Solution Found !
I make the character like a 2D in (( X-Z Plane )). Its just like a 2D object.
So in fpx export settings and in Armature options , i set primary bone axis to X axis and secondary bone axis to Z axis.

Now legs are okay !