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

The Twilight Render Team shares tips, ideas, helpful hints, and more on using Twilight Render
Post Reply
olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

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

Post by olishea » Sun Oct 10, 2010 1:13 am

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 13343 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 13343 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 13344 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 :)
Oli

olishea
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Re: Shrine-university project

Post by olishea » Sun Oct 10, 2010 3:13 pm

high res version of exteriors:

(again, pretty much raw twilight output)

Spherical panorama by Ralph Ames of www.virtualmidlands.co.uk
Attachments
final render 1_small.jpg
final render 1_small.jpg (566.21 KiB) Viewed 13480 times
final render 3_small.jpg
final render 3_small.jpg (620.33 KiB) Viewed 13476 times
Last edited by olishea on Sun Oct 10, 2010 5:41 pm, edited 1 time in total.
Oli

jsmda800
Posts: 18
Joined: Sat Sep 11, 2010 7:59 pm

Re: Shrine-university project

Post by jsmda800 » Sun Oct 10, 2010 5:33 pm

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

that will be a marvelous space to be in!

d12dozr
Posts: 168
Joined: Fri Aug 28, 2009 8:55 pm
OS: Windows 8
SketchUp: 8 Pro

Re: Shrine-university project

Post by d12dozr » Mon Oct 11, 2010 12:31 am

:^: good renders, excellent tip
-Marcus

Sepo
Posts: 177
Joined: Sat Sep 19, 2009 7:06 pm

Re: Shrine-university project

Post by Sepo » Mon Oct 11, 2010 8:51 pm

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
Posts: 768
Joined: Mon Sep 21, 2009 8:54 am

Re: Shrine-university project

Post by olishea » Tue Oct 12, 2010 1:35 am

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.
Oli

Fletch
Posts: 11711
Joined: Fri Mar 20, 2009 2:41 pm
OS: PC 64bit
SketchUp: 2016-2021
Contact:

Re: Shrine-university project

Post by Fletch » Tue Oct 12, 2010 8:58 am

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.

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests