Solved by ptrblck in post #2 
              
              
                This should work: 
A, B, C = 6, 6, 4
x = torch.zeros(A, B, C)
idx = torch.tensor([[0,1], [1,0], [3,4]])
val = torch.tensor([[1,1,1,1],[2,2,2,2],[3,3,3,3]]).float()

x[idx[:, 0], idx[:, 1]] = val
print(x)
> tensor([[[0., 0., 0., 0.],
           [1., 1., 1., 1.],
           [0., 0., 0., 0.],
         …