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Isolating the background in an animation?


branskyj
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Hi all,

I am doing a product visualization (3ds max and VRay)- its a day shot of an office, light is coming through the windows, the product inside the office, panning camera. I have right now set-up a HDRI image as a background to contribute to the GI.

My goal is to to render the final animation of the camera approaching the product and then to replace the static HDRI in the background with a real video (with matching angles)in say Adobe Premiere. The problem is that I cannot isolate the background so that I can create a mask which later on to be used in Premiere for the new background.

I have never really done that and don't know what the normal workflow is. I tried using Render Elements/VRayBackground but that only works if there are no windows in the scene.

What are my options?

Thank you for the help guys.

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If it's not in your alpha channel, ie which means the hdri isn't a vray light.

 

Use vary multi matte elements. (u have to set the "hdri" image/plane etc to match the g buffer to the selected channel. A quick google search will show tuts for it. )

Or install a script called render mask on scriptspot. (I still use it in every max project to get last min passes or mask)

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Thanks a lot for the help fooch,

I just tried Render Mask and worked like a charm. Just to make sure I got it right- when using it I have to delete the windows from my scene, right? Otherwise the mask is completely white thus unusable.

 

Cheers.

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I think you could simply use the HDRI in the environment rollout and leave the Max environment at its default with no maps and a black background. Then save out in a format that support alpha channels.

 

I think matting down the alpha in Aftereffects from an element might produce a cleaner more controllable result, but simply using the image alpha will take the least amount of thought.

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