Using photo's for HDRI's (Purely Experimental)

mjb · October 11, 2016, 03:57:51 PM

Can't find matching HDRI's for your photo's? Make them!
1) take a photo from www.unsplash.com (search 'road'.. there are loads)
2) in Photoshop, make a duplicate and place it next to the original, and then mirror it so there is no seam (So you now have an image x2 the width of the original)
3)Image>mode>32bit
4)save as HDRI
Rotate the image so there are no obvious reflections in the right place

I've done this a LOT!

JimmyToTheBe · October 12, 2016, 01:21:50 AM

Quote from: mjb on October 11, 2016, 03:57:51 PM
Can't find matching HDRI's for your photo's? Make them!

This is good to know its always difficult to find decent images for vehicle setups that are free to use.
I'm sure this will come in handy.

Despot · October 12, 2016, 02:03:24 AM

This is absolutely ridiculous... the worst advice ever in in the history of computer graphics.

It's actually akin to saying something like 'OH, I know how to keep my head warm, I'll set my hair on fire!!'

You cannot just simply convert to 32 Bit in PS, then save out with a .HDR extension and hey presto !! - it just doesn't work like that...

I'm not even going to explain why, please read this :

https://en.wikipedia.org/wiki/High-dynamic-range_imaging

You may think that your renders look OK using this 'method', but they don't. Also, because the source images you are using are probably not equirectangular, any reflections from it will be incorrect.

Honestly, you are passing completely erroneous information to the whole KeyShot community and beyond - one of the mods should delete this thread...

Chad Holton · October 12, 2016, 05:56:45 AM

Whoa... take it easy, John. I agree that you shouldn't upconvert the image (because the color information isn't there) but this format (HDR) is needed for KeyShot and probably the reason it was upconverted. I think we can add to this thread with some helpful information.

A good while back, maybe even before KeyShot 2, there was forum user (and professional photographer) that would take HDR images and add in buildings/trees and such to get the reflections they wanted (basically just using the sky from the HDR) and would get some great renderings. With the current Pro version, you can add image pins to get a similar result. Probably not the best way but sometimes you can only use the tools you have or just want a quick shot.

mjb · October 12, 2016, 07:32:12 AM

lol, crikey. And of course, I know the difference between high dynamic range and a standard photograph.
Well, personally, I think they look interesting - having spent several years using backplates and matching environments...
Disclaimer: This information is for personal use only and under no circumstances to ever be used or shared in the public domain under penalty of death.

Seriously though, sorry I upset you John. but y'know.. uh.. it works for quick shots, so why not? No-one has to actually do it, it just something that I like doing. No harm.

mjb · October 12, 2016, 07:50:26 AM

..and yes Chad, that's the reason - to save as an EXR or HDR it has to be upscaled.
John's comment about the reflections are fixed by doubling the width of a high res 5000 px wide photo and it just works.. Never had any reflection problems. Yet

Chad Holton · October 12, 2016, 07:58:21 AM

.... really digging the B&W shot, BTW.

mjb · October 12, 2016, 08:04:17 AM

Hey thanks

mjb · October 12, 2016, 08:18:26 AM

I've modded the thread title John, hope that's better.
Apologies again for the upset..

Despot · October 12, 2016, 08:42:35 AM

QuoteWhoa... take it easy, John. I agree that you shouldn't upconvert the image (because the color information isn't there) but this format (HDR) is needed for KeyShot and probably the reason it was upconverted. I think we can add to this thread with some helpful information.

QuoteSeriously though, sorry I upset you John. but y'know.. uh.. it works for quick shots, so why not? No-one has to actually do it, it just something that I like doing. No harm.

Yes, I could have been a lot quieter and calmer, I can see that now.... I didn't mean to upset MJB or you, Chad...

I've never mentioned this on the forum before, but I had a brain tumour a few years ago and it seems to have altered my personality immensely, I'm much more emotional and prone to, well, 'outbursts'. So I'm sorry if that offends. But I'm also very passionate about what I do and I think that's obvious.

Again, I apologise.

J

mjb · October 12, 2016, 08:48:47 AM

No, not at all John.
And I'm very sorry to hear that you had to go through that, can't really imagine how traumatic that must of been.
All the best, and seriously, no need to apologize, it's all good

Sincerely, Matt.

Will Gibbons · October 12, 2016, 08:59:40 AM

As chad mentioned, I also really like the results of the black and white image of the rear of the car. Whether it's technically 100% right/accurate or not, I like the results.

NM-92 · October 12, 2016, 12:42:53 PM

I have to give this a shot ! I always tried to fake some reflections with the hdri editor and image pins.

CPHGNrenders · October 21, 2016, 01:21:13 PM

This could help me too. Thanks for the tip!

DMerz III · October 21, 2016, 01:40:35 PM

Nice technique for the shortcut, thank you for sharing!

I do see Despot's point about the misinformation. These maps would be useful as "reflection" maps vs "lighting" maps, just needed the quick change in terminology. So it's still a useful method, and as Chad mentioned, you could make up the difference in the lighting with HDRI Editor Pins.

Again thanks for sharing!