ScreenshotsFor Battlefield, the developer chose to only augment reflections using raytracing. Everything else is rendered just like before. Visually, RTX greatly improves the quality of reflections. This is unlike reflection maps in rasterization and is being rendered in real-time. You see reflections of yourself on non-planar surfaces, such as the body of a car or window panes. Reflections have existed in 3D graphics since DirectX 9.0c, using various tricks; for example, reusing data from screen and painting it on to a reflective surface (screen space reflections). This approach would fail often because it could mirror only parts of the scene that were already visible on-screen somewhere else. Mirrors (planar surfaces) were created using "portals," which are basically drawing the scene from the viewpoint of the mirror a second time and then flipping it. It was impossible to implement portals on non-planar surfaces, and it was especially difficult to create a "hall of mirrors" effect (where a non-planar surface is reflecting your image differently). You could warp a plane viewport over a non-planar surface, but it was inaccurate and very taxing on the machine.
The window pane is reflecting the scenery behind the player, which wasn't possible before, without RTX. At the same time, you see part of the scene behind the glass rendered and merged accurately with the reflections.
Here, you see fine examples of reflections from the surface of a car's glossy paint job. This certainly looks more realistic than the red car in the RTX reveal tech-demo. You can see how each surface has a unique way of reflecting the image of your playable character. Warping a planar screen space reflection cannot achieve this. You can even see which weapons the characters are holding!
Here, you notice a scenario where there isn't enough ambient light to reflect you, and the room behind the window pane is too dark.
Note the scene setup: burning truck on the left and a car on the right. On the car's surface, you can see a red reflection, which is the red trim of the open door.
Now, we moved to stand right in front of the car, with the burning truck behind us. Note the faint reflection of the flames slightly above the crosshair. Also, the reflection of the red trim that we saw before is gone now, so it's not just some pre-baked visual texture effect.