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I realised that the shadow catcher for cycles doesn't actually catch emision or act as a diffuse bouncer from the HDRI, as the matter of facts it only catches shadows as stated at https://devtalk.blender.org/t/lets-finally-fix-the-shadowcatcher/691

Does anyone know any tips, tricks, hacks or code to make an object catch emision and light objects of Blender? I intend to use it for VFX and videos not still images.

Using camera projection was my go to for simple environments and relatively sturdy camera movements. But for actual production shots with really aggressive camera motion and perspective distortions and relatively complex scenes, reprojecting the image was required for most of the frames since the distortion will be noticed as projection only works per frame not as a video(don't know about this for sure, if you guys know a way I can continuously reproject the image onto my 3dset that would help) but as of now that's not remotely an efficient way to do it.

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  • $\begingroup$ Does this answer your question? Is there a way to utilize emissions in VFX? $\endgroup$
    – Leander
    Commented Jan 17, 2020 at 14:41
  • $\begingroup$ Look at how the linked question uses the first two layers. By subtracting the environment "clean" and "shaded" we can get the lighting difference. If I misunderstood your question, an edit detailingthe difference would be nice. $\endgroup$
    – Leander
    Commented Jan 17, 2020 at 14:42
  • $\begingroup$ Edited my question, my intention is for VFX and on a video. Reprojecting the image then animating the texture is seriously not optimal and time consuming. The suggested thread is working on an image not a video. $\endgroup$
    – Reuben Tilahun
    Commented Jan 17, 2020 at 15:33
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    $\begingroup$ It's a bit of work, but you can use renderlayers for that. Create a plane with a diffuse material that's close to black, it will catch all the light, then use screen or add to overlay it on top of your original footage. If you need the light to be obscured by objects, you can add them to your render layers with pure black emission or holdout shaders .You'll need to render twice this way, but it's better than nothing $\endgroup$
    – Frederik Steinmetz
    Commented Jan 17, 2020 at 15:48
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    $\begingroup$ Looks like the UV project modifier does do projection with an aminated plate. I just played with a Blender scene, with a camera tracked in Syntheyes projecting the undistorted background plate on to the ground mesh created in Syntheyes (and modfied in Blender)- and it worked OK. Looks to work in Cycles & Eevee. You have to un-check 'shadow catcher' & use a Principled BSDF or whatever shader if you want to see it with shadows though, and then it gets lit & all the other surface parameters from the shader (so it looks horrible compared to the clean plate). $\endgroup$
    – MarkS
    Commented Jan 18, 2020 at 5:35

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