Ndisplay set the viewport to match the physical monitors

Testing Ndisplay because I would like to be “rendering real-time content through multiple simultaneous displays” Yeah! -with something more complex later on so to begin 1 PC and 2 Monitors.

So my physical monitors are like this :

in Windows display settings it’s like this - the 4K monitor marked 2 below is set to be the main monitor.

in NDisplay config 3Dview (I’m using unreal 5.3) I set it like this:

the NDisplay cluster has one Cluster Node with 2 viewports:

But how to set the viewport settings to get what i want???
There are multiple settings that might or might not control what I need. I can somtimes get it to go on the smaller left monitor. But its displaying the “front” view content on the left monitor. If Windows treats main monitor as 0,0 position then setting VP 0 to -1920 should move it over- but negative values are not allowed, in Viewport position, but are allowed in Cluster node position.

Can anyone help?

ok think i have a solution.

monitors need to be set to 100% scaling.
For a single PC with 2 monitors it needs one node with 2 x Viewpoints.
add the viewports for monitors left to right (I think)
For my setup I select the Cluster Node and set the Position to -1920, 0 like this pic:
(you need to enable Allow Manual Placement and Allow Manual Sizing)

Similarly the Node : is set to position -1920, 0 with the size reflecting the 1920 & 3840 monitor resolutions so size = 5760 x 2160

then the viewports - setting the motior resolution - my small one is low down.

…so it looks offset to the left in the Output Mapping Window

…then the big monitor viewport is shifted over 1920

and that is working for me.