Monitor Setup Debugging

Monitor Setup and exported viewports in DCS are not technically related to Helios (as of Helios 1.4.2020.0315) but create problems for significant number of Helios users. This page will collect relevant background information and provide some instructions for how to verify each separate concept. Following these instructions will help diagnose problems and allow others to help get a misbehaving Monitor Setup in line.

[Note: this version of this document is just a rough draft and may be inaccurate. Please help improve it.]

1. Windows Desktop Layout

Windows allows the user to arrange their "Multiple Displays" as they want to form one virtual desktop. This means you could theoretically have two monitors that are diagonally aligned and have a huge gap between them in the Windows Rearrange Multiple Displays settings. Most people don't do that, because they want their mouse cursor to be able to move from one screen to the next smoothly and they use all their monitors as part of their Windows Desktop. However, since it is quick and easy to verify and we need the information later anyway, it is a good idea to always verify what is going on with Windows.

When helping anyone (including yourself) to configure Monitor Setup or additional Viewport exports, always start with a screen shot. Don't run DCS yet, because it may change to a full screen view with a different resolution. Simply hit Print Screen ("PrtScn" or similar) on the keyboard with some windows on all the monitors that are part of the Windows Desktop, so you can tell the difference where monitors are mapped. Paste this screenshot into Discord if you are getting remote help or into any paint program if you are working on the machine yourself. The built in Paint app (pbrush.exe) in Windows works fine. Open Discord or the paint application of your choice and hit paste. You can now see the monitor layout, and you can measure the sizes of each screen as they actually are (as opposed to how you think they might be configured.)

2. DCS Screen Resolution

DCS does not support rendering to multiple separate regions on different monitors. If you are doing any interesting monitor setup (such as exporting Viewports to extra screens,) you will be running DCS in Windowed mode. In this mode, you can configure DCS to render any one rectangle you want, but only one. You can even edit the options file directly and put in really silly rectangles, but DCS will offer you all the ones that "make sense" as "Resolution" settings in the System options. It is important to understand that this "Resolution" is a rectangle starting at the top left corner of your Windows desktop and it needs to include every area where you plan to put DCS views, including the main 3D view and any additional Viewports. As of DCS 2.5, DCS also allows you to configure a Resolution that does not include the top-left corner of your Windows desktop. If you set your resolution to something less than your entire desktop, then DCS will try to fit it onto your desktop, starting with the main display. It will also try to include all areas where you actually mapped viewports. However, this process is unreliable and confusing if you have oddly an oddly shaped Desktop. If you don't need to free up your left-most monitors for other tasks, it is best to start out with the resolution that includes your entire Windows desktop.

You can use your screenshot from Step 1 to measure the size of the rectangle you need. For example, if your left-most screen is set up lower than the other screens, you will need to include the empty space above it in the screenshot, because DCS can only do a rectangle. Therefore, select the entire "bounding box" for all the displays you want to include. If you don't like that concept, just go in your paint program and use the rectangle select tool to measure a rectangle that includes every screen where you want to display stuff. The rectangle should start at the top left corner of your screen shot, even if you don't plan to put any DCS stuff there. That's why it matters what your monitor setup is.

In DCS' System Options, select the resolution that is at least as large as the numbers that you measured. If there isn't one that matches exactly, choose a larger one. It has to be bigger in both numbers (both width and height.)

If you are an advanced user, go ahead and hack up the display options yourself and make whatever custom rectangle you want. But then you are on your own.

3. DCS Monitor Setup

Now run DCS using whatever Monitor Setup you are trying to install. Probably things will be very wrong unless your monitors happen to be exactly the same as those of the person who created the monitor setup. That's fine for now. Run DCS and Helios and start the profile you are installing. Take another screenshot with print screen and share it with anyone helping you. Using this screenshot and your first screenshot, we can measure where things are and where they should be.