Hello!
Just in case someone wants to do ortho projection with ndisplay, I found the “manual” projection policy was not enough in my case, only allowing to set the frustrum but not really setting the viewport as ortho.
To get an ortho view for your VP:
First step is to head to your ndisplay config file, select the viewport you want ortho. In the details panel select “Manual” for projection policy. Then immediately after, select “Custom”.
(Selecting Manual first and then Custom allows Unreal to fill in the required parameters).
Next step is to fill in the matrix.
I found the matrix to be slightly different in Unreal than in WebGL or Unity, so you can use the function “Calculate Projection Matrix” from any Blueprint to get your projection matrix. You can split the input structure to get all the parameters you need, and you can simply print the output to the console.
The output of that function will give you the Matrix you need.
I’ve found that for viewports to refresh their view in the ndisplay editor, I have to compile and close the tab and reopen the config.
After reopening, your VP should show an ortho view with your parameters.
Cheers!