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Casting Shadows using HDRI
Hi – I have tracked some background footage and rotoscoped out the foreground objects.
I’ve done some test renders using default lighting & basic 3d objects and I’m happy with my tracking and rotoscoping.
I’m ready to comp in my 3D assets in C4D.1:
I have a hdri panoramic image shot with the same lens as my footage (tokina 11-16) and taken in the same location.
I’m trying to position the hdri image within C4D so as it lines up with the first frame of my video plate. This is proving difficult and the objects in my hdri image appear to be further away than the objects in my video plate scene. Do they both have to sync up perfectly at the start or is it just a matter of getting them roughly aligned ?2:
My second question relates to adding in shadows.
Anything I’ve worked on to date with matchmoving & HDR I would have added in some virtual lights to cast shadows onto a ground plane with a shadow catcher material.
Any of the posts I’ve checked on this topic they all seem to be 4-5 years old. They all say that its too difficult to base the shadows in your scene from the hdri light and even if you do manage to get it working the results are not great. is this still the case – is the best way to add virtual shadows to ‘fake it’ positioning basic 3d lights or is there a conventional method currently being used ?Even though I’m using C4D I would have no problem switching to Max or Maya to harness the shadows from my hdri light if it was a straight forward process.
Any suggestions or advice would be great.
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2 Replies
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1. As far as lighting and reflections go, I wouldn’t worry too much about precise alignment.
2. For shadows I don’t think anything has really changed in the last 4-5 years. You’re still better off adding some shadow-only lights rather than trying to comp the HDRI shadows onto the background. I don’t think it’s any different in the other programs, but I could be wrong about that.
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Thanks
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