For those who may wondering how to create a realistic background for an architectural interior scene, and like me, you didn’t find a viable HDRI, i.e., it wasn’t the right height or captured the scenery you wanted, this is what I tried, and I think it will work for my scene.
Looking back at an Archi Interior file that I previously downloaded from the Marketplace to reverse engineer (great tip for newbies, by the way), I stole this concept of using a half cylinder shaped mesh object with a masked cityscape image attached to it.
For the record, I’d love feedback on what others think about this process as an option to replace HDRI backdrops. Also, what I should divulge before I continue is that my final project is not a game. The end result will only be a video of a slow camera pass and a few still images for my portfolio, so if you’re curious if what I did will work for your game, I’m going to go out on a limb and suggest, perhaps not.
Step 1: I use Blender as my 3D DCC, so I created a mesh cylinder and removed all faces except for one side, keeping as much of the curve as possible (approximately 15-20 degrees), and I made the mesh taller than wide. I then created a material slot for the faces that I wanted pointing toward the camera in UE4. I exported the mesh as a FBX.
Step 2: Online, I purchased an iStock photo of the perfect skyline for my use. I searched for a photo that was very high resolution and matched the lighting I wanted in UE4.
Step 3. In Photoshop, I masked out the sky and made certain that the horizon was blurry, using a vertical gradient to make the horizon sort of fade out (i.e., atmospheric perspective). I applied a Gaussian Blur to the entire image. (Note: I had to keep finetuning the PSD file to get it to look realistic, e.g., adding haze, desaturating the image, etc.).
Step 4. I imported the FBX file that I created in Blender and the PSD file into UE4. I created a Material that pointed to the PSD file. I dropped the FBX file (the half cylinder) and applied the Material to it, adjusting the cylinder on the Z-axis to my liking while looking through the windows in my scene.
So far, I’d have to say that I’ve got it looking pretty good. Again, I had to keep re-visiting the PSD file and making minor alterations, reimporting the PSD file each time in UE4.
To revisit the question if this will work for a game, I’d say no, but you be the judge.