For the modelvdp, remove the line connecting the Product block with the Gain block.

load_system('vdp'); delete_line('vdp','Product/1','Mu/1');

For the modelvdp, remove a line using the line handle. You can get the line handle using different techniques.

load_system('vdp'); h = get_param('vdp/Mu','LineHandles'); delete_line(h.Outport(1));

Get a line handle when you create the line. Delete the line using that handle.

a = add_line('vdp','Mu/1','Sum/2'); delete_line(a)

You can use a point on the line to delete the whole line.

Find the port coordinates for the block Mu in the modelvdp.

open_system('vdp'); mu = get_param('vdp/Mu',“ portconnectivity'); mu.Position

ans =1×2190 150

ans =1×2225 150

The line that connects the Mu block to the Sum block starts at the output port, which is at (225,150). You can use any point to the right of that point along the samex-axis to delete the line.

delete_line('vdp',[230,150]);

Usedelete_linewith branched lines to remove the segment for any connection.

open_system('vdp');

delete_line('vdp','x1/1','Out1/1')

delete_line('vdp','x2/1','Mux/2')

delete_line('vdp','x2/1','Product/2')