Hi guys! I need your help. I am working with Zoom platform, changing the image of other participants using Touchdesigner. In order to manipulate their image in real-time, I´m using the screen grab TOP and an NDI out as a virtual camera for zoom. I need to use two monitors, so in the first one, I will have the zoom platform and in the second one Touchdesigner, so I can change the images. However, when I connect the two monitors, the screen grab captures both, as a result in the NDI out I get half image from the first monitor and half from the second one. How can I capture only the image from one monitor? Many thanks for your help!
Use a cropTOP to remove ecces screen from your top 
Screengrab TOP has already crop options in its parameter
The Experimental build of TouchDesigner 2020.40000 has per-monitor selection, and per-application selection (assuming the app is not covered by another app).
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Thank you for your reply, but this didn´t work, when I crop the image from one monitor, the other one disappears or breaks down.
Did you try the crop parameters on the Screen Grab TOP? These will be a lot more efficient that using a separate Crop TOP because touchdesigner will only capture the portion of the screen inside the crop region rather than capturing both monitors and then discarding one screen afterwards.
When you say the other one disappears or breaks down, do you mean the image on the monitor is affected by the cropping? Or is it something inside the captured image in touchdesigner that is being corrupted?
Hi Rob, thank you for your reply. I tried the CROP parameters on the Screen Grab TOP, but this made that the captured image in touchdesigner was affected, and I was not able to see the image on Zoom, which was performed on the second monitor.
Sorry, I might not be understanding the problem exactly. From what you said, you’ve got a Screen Grab TOP that is capturing two monitors: one with zoom on it and one with TouchDesigner, and you want just the part of the image that comes from the Zoom monitor? Normally, for this case you should just be able to adjust the Left/Right parameters on the Screen Grab TOP so that only the Zoom portion of the image is being captured (or use the new Source menu in the 40k experimental build).
But I gather this isn’t producing the results you are looking for? Are you able to capture the problem (maybe with a cellphone camera) to demonstrate what is going wrong? You can message me directly on the forums or send files to support@derivative.ca if you do not wish to share images publicly.