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Scale an HDR Spherical Image to Match Your Scene (How To)

Posted: Sun Oct 10, 2010 1:13 am
by olishea
I have blurred the spherical panorama as to not infringe any copyright etc.

So here is a typical spherical panorama image (original is 14000 pixels wide). I rendered my model and the hdri was too close. The background was blurry and out of scale.
sample1.jpg
sample1.jpg (43.37 KiB) Viewed 28159 times
Now, to make your hdri look further away when rendered:

Open in photoshop, make the image a layer. CROP OUTWARDS (make sure you scale keeping proportions, so hold shift and alt to crop from the centre of the image). your resultant image should be larger than the original with a blank border. MAKE YOUR NEW BORDER BLACK. The new extended image is now 17000 pixels wide.
sample2.jpg
sample2.jpg (42.58 KiB) Viewed 28159 times
If you want to make your image look even further away......just make your black border bigger (again, crop outwards)....This one is 18,800 pixels wide.
sample3.jpg
sample3.jpg (41.05 KiB) Viewed 28160 times
You now have complete control of how far away your background will be ;)

IN ESSENCE, YOUR HDRI STAYS THE SAME SIZE.....YOU JUST HAVE TO MAKE THE BORDER BIGGER TO SHRINK IT IN THE RENDER :)

Re: Shrine-university project

Posted: Sun Oct 10, 2010 3:13 pm
by olishea
high res version of exteriors:

(again, pretty much raw twilight output)

Spherical panorama by Ralph Ames of www.virtualmidlands.co.uk

Re: Shrine-university project

Posted: Sun Oct 10, 2010 5:33 pm
by jsmda800
wow, very nice! incredible background and great tip...

that will be a marvelous space to be in!

Re: Shrine-university project

Posted: Mon Oct 11, 2010 12:31 am
by d12dozr
:^: good renders, excellent tip

Re: Shrine-university project

Posted: Mon Oct 11, 2010 8:51 pm
by Sepo
Oli... I am not sure that I understand what you mean by keeping the scale of the image the same. The thickness of the black frame is thinner at the top and bottom than sides.. Would enlarging the canvas size equally do the trick? Have you discovered some sort of rule of thumb in terms of enlargement?

Re: Shrine-university project

Posted: Tue Oct 12, 2010 1:35 am
by olishea
no rule of thumb.I just did it until the scale looked about right!

Sid I just cropped outwards using alt and shift....suppose you could do it with canvas size. I just kept having to tweak it til I got it right so I used crop.

For example: say your hdri is 10,000 pixels wide. That image must remain that size at all times. just increase the border size......so you will end up with a 10,000 pixel wide hdri set within a larger frame.

Re: Shrine-university project

Posted: Tue Oct 12, 2010 8:58 am
by Fletch
It should be pointed out (for those beginning with HDR) that this tip/technique WILL END UP WITH BLACK showing in your HDRI reflections or if you are aiming your camera in the direction where the borders will meet. As the image is wrapped around the inside of the sky sphere, the top, bottom, and "seam" edge of where this border will meet itself on the sphere will be black, and little/no light will come from that portion of the HDR. So run some quick prelims, and use the rotation slider in the Sun/Sky/Lighting Dialog of Twilight to adjust the angle of view of the HDR.

Re: Scale an HDR Spherical Image to Match Your Scene (How To)

Posted: Mon Oct 09, 2023 7:37 am
by Fletch
In the latest versions of Photoshop now there's an AI option to crop an image outward that will actually attempt to automatically fill in the missing information while leaving the original image in full resolution, so you would not have black strips in your reflections. 8-)
I do not believe it can do this on HDRi, but it should work with any .jpg