Easily mask images after render?

Hi, I have a water splash scene with a glass and some background, but I just want to use the water splash image for post production in Photoshop. Once I render with everything , it becomes difficult to mask the splash as things in the background and glass makes it hard to select. But if I hide those other materials in Render, than I dont get the effetcs they give like reflections and shadow…I was wondering if there’s a way to be able to get only the things I want in render, but with the reflection shadow vs. effetcs of other elements in the scene as well. :no:
Please help, thanks

You could give the splash material a material id or the object and object id. Then in the render passes enable the id pass and use that to create a mask in the compositor. This would then mask the splash

thanks for reply, i was wondering if you could describe it a little bit more explicitly :o I have recently started using Blender. I’ll be fine but just a little bit more help would be great :slight_smile: