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

[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 (43.37 KiB) Viewed 20708 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 (42.58 KiB) Viewed 20708 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 (41.05 KiB) Viewed 20709 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

[olishea]

high res version of exteriors:

(again, pretty much raw twilight output)

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

[jsmda800]

wow, very nice! incredible background and great tip...

that will be a marvelous space to be in!

[d12dozr]

good renders, excellent tip

[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?

[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.

[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.

[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.
I do not believe it can do this on HDRi, but it should work with any .jpg