HighResShot w/ Transparency on Isolated Objects?

First a little background info:
We are trying something new at our studio and attempting to see if we can eliminate the need for offline rendering. Normally we use Vray or Mental Ray but for our needs the renders we kick out don’t need to be perfectly crisp. In a perfect world, something like UE4 would be fantastic because we could rapidly iterate with our other departments. What we need to do in a nutshell is isolate individual objects/groups/prefabs in a camera view and render each one with alpha, and without compromising the lighting or exposure. So that after bringing each image into Photoshop, they can be layered together to form the same render visible in the UE4 editor, with all objects present. We would also need to render at UHD and 7k, both of which are possible and look great using the ‘HighResShot’ command. What I’ve learned so far:

  • We can render our spec sizes, UHD and 7k
  • We can render with limited transparency, using the custom depth as mask checkbox
  • We can render with the Buffer Visualization Targets, which is awesome.
  • When rendering with alpha, it keeps any objects in front of the target object, clipping off at the target objects alpha edge. It doesn’t actually isolate the object. (see attached)
  • I can’t seem to use ‘custom depth as mask’ when running the game. It only seems to work when the editor is active.

So my question(s) include:

  • What is the best method to approach the above problem?
  • How can I procedurally toggle the Render CustomDepth of objects in view of the camera, leaving one on at a time?
  • How can I make objects invisible to camera, but keep their render properties so they affect their surroundings, to isolate an object when taking a snapshot?
  • Are there alternative methods to solving the problem, like using renderToTexture for example.

Thanks for your time. I’m still very new to UE4 but I already love how powerful of a tool it is. Any help is greatly appreciated.

Hey everyone. I realize that asking questions about using UE4 as on offline renderer must get a giant eyeroll among the engine devs, but it really is a great product, which is why the possibility for these kinds of features gets folks like me excited to use UE4 as a content creation platform, not just for games. I realize it’s a pretty loaded set of questions, so maybe I can start with one smaller question and work from there. I’d like to do my own legwork to have this function, but if it is not possible without major engine tweaks, I’d like to know now before sinking lots of energy into trying this. So…

Is it possible to isolate an object and render an alpha screenshot of that object, while maintaining it’s lighting information?

Thanks for your time. I appreciate any and all insight.

Hey JJChalupnik,

did you ever came to a solution for this topic? I am working on a similar problem like you can see here: https://forums.unrealengine.com/development-discussion/c-gameplay-programming/1472236-runtime-screenshot-with-alpha-mask