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Clipping reflection distance in floor?

Message 1 of 4
342 Views, 3 Replies

Clipping reflection distance in floor?

I'm rendering out stills of some big machinery on a white floor that includes semi-blurry reflections in the floor. The client wants to place these seamlessly in a white background, so he doesn't want reflections that are so long they end up cropped at the bottom of the frame. Is there a way to limit the distance of a reflection, at which point it fades out? AFAIK Arnold wants to show the entire reflection to the top of the object. The reflection WILL essentially disappear if I crank up the Specular roughness, but at that point the reflection becomes so indistinct you can't make out ANY contours of the machine, even where it touches the floor.

This shows the gist. The top is the straight render from C4D. The bottom is the look I'm going for, created using masks and some selective blurring in AE.


Such masking would mostly work for stills, but I could see that being almost impossible for an animation. Any help is appreciated. Thanks!



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Message 2 of 4
in reply to: shawn

Not sure if your scene is too complex, but a possible solution was to have a smaller object that would provide the reflections. So main object is rendered, but isn't reflected, a second smaller object is hidden for the camera but reflects. Hope this makes sense

Lead Enviroment Artist @Axis Studios

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Ciro Cardoso


Message 3 of 4
in reply to: shawn

Increasing the specular_roughness should help with that.


Lee Griggs
Arnold rendering specialist
Message 4 of 4
in reply to: shawn

Thanks for the replies. Simply masking the reflection seems to have worked for the client.

As I wrote, I did try increasing the Specularity roughness. That does fuzz out the reflections towards the bottom of the frame, but by that point the reflection becomes too indistinct to recognize any details of the machine, even where it's touching the floor.

I was hoping there might be some other control that would somehow limit how far a surface can "see" a reflected object, but I don't think such a thing exists as Arnold is trying to realistically replicate how photons work on objects. Maybe a second pass with some sort of fog layer would fake that, but that's way too much work for this project.



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