Sky HDRI zoon-in / zoom-out….?
Posted: 17 May 2020 10:49 PM   [ Ignore ]  
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Joined  2019-09-02

Hi,

Using sky HDRI in a scene with shadow catcher.

Is there way to do HDRI zoom-in or zoom-out to fit the HDRI area in my object placement…?


Thanks,
Imran.

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Posted: 18 May 2020 09:18 AM   [ Ignore ]   [ # 1 ]  
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Hi Imran,

The Sky Object has no option to tile or to change the U, V length, as it has no UV data, to begin with.

There are two ways, but one has the need to replace the Sky object with a large sphere.

The first example works photographically. This means that at the moment we change the distance to our subject and change the field of view, we create a different relationship to the context (here the Sky). Since the sky object is rather infinite than close, this will produce the effect of the magnifying eh background.

The second example replaced the Sky with a Sphere, a large sphere. Now we have UV data to work with.
Since the Length U, V, will “move” the image around, we need to counter this with the offset values.

I have made a screen capture to illustrate this effect, plus project files:
https://www.amazon.com/clouddrive/share/1zPb8eA2iOiQF2m0HxuMzy4kxskydtWsnCqraaAAtgO

Please note that the second version will not reproduce the light a 360x180ยบ HDRi typically produces, as it is either cropped or tiled. Often there is a suggestion to split HDRi (light) and HDRI background, but it produces a more complex set up.

You could also render the background in the right size (Focal length) without the foreground object and then use the rendered image on a background object.

You might need to place your HDRi into it.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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Posted: 18 May 2020 09:36 AM   [ Ignore ]   [ # 2 ]  
Total Posts:  78
Joined  2019-09-02

Yes… Thanks for your detailed reply.

Regards.
...

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Posted: 18 May 2020 09:55 AM   [ Ignore ]   [ # 3 ]  
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You’re very welcome, Imran, thanks for the feedback.

Here is a short clip, showcase what I mentioned above, with rendering the background to your needs.
Note that the resolution of freely distributed HDRIs are typically not very high, so the magnifying eh background has limits. The other way around, seeing more from the context, is easier, and often even better.

Screen capture
https://www.amazon.com/clouddrive/share/5jOSWnmRNvI3bB9jqm8FcTHfD0ZOfHusQGDZ2OxYuMs

Enjoy your project

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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Posted: 18 May 2020 09:59 AM   [ Ignore ]   [ # 4 ]  
Total Posts:  78
Joined  2019-09-02

awesome….! nice idea…. first render as back plate and then place it with object!

Great.

thanks.
...

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Posted: 18 May 2020 10:00 AM   [ Ignore ]   [ # 5 ]  
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Thanks again, Imran.

If there is anything else, please let me know. I’m happy to look into it.

Cheers

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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