Compositing reflections for an object that will change frequently in an otherwise static scene

[daniel2SH2D]

Hi

Imagine a scene with a fair few reflective materials in it, and a 'hero' object that needs to change regularly (textures only, not geometry - that's always the same).

The scene itself is quite heavy, and only really needs to be rendered once - then the 'changing object' can be rendered separately and composited into the scene again and again without having to re-render the whole scene each time...

EXCEPT for all the reflections in various surfaces in the scene...

Take a newspaper front page as an example: always the same scene, same newspaper, but the text and photo on the front page changes all the time, and this needs to update across all the reflections in the scene.

Is there any way to render just the object and its reflections in the scene, and composite the reflections along with the object, WITHOUT having to re-render all the reflective geometry from the scene again? What would that workflow look like?

Hoping my question makes sense! Thanks in advance.

[peter_horvath · Accepted solution]

Don't think there is, I'm afraid. There's a 'Render Selected Object' feature in Render Settings > Advanced, but it does not render reflections. You have to select and re-render all objects as well which reflects the hero object.

[daniel2SH2D]

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[daniel2SH2D]

Thanks Peter!

I got *kinda* close using Shadow-catchers with the Indirect Specular option checked, but couldn't get quite the right 'look' to the reflections, and it was in a much simplified scene, so I had to just render out whole scenes in the end, but might return to the shadow-catcher attempt if time permits and see if I can nail the difference in reflective 'tone' that I was observing.