topic Re: lightning HDRI vs Sky in Visualization

lightning HDRI vs Sky

Anonymous — Thu, 11 May 2023 12:58:17 GMT

Is it only me but I have the feeling that we have better scenes with Sky than with HDRI library images. I can obtain much better and crispy images using Sky than HDRI. Is it only my feeling?

Re: lightning HDRI vs Sky

Erwin Edel — Thu, 23 Aug 2018 08:03:19 GMT

I think the HDRI images in the library are not that great quality, but I gave up on trying to find a good HDRI that matches typical surroundings for our projects.

Re: lightning HDRI vs Sky

Eduardo Rolon — Thu, 23 Aug 2018 11:10:12 GMT

Good place to buy high quality HDRI images

https://www.pg-skies.net

Re: lightning HDRI vs Sky

Erwin Edel — Thu, 23 Aug 2018 11:19:02 GMT

Those look interesting, as they don't show the terrain, which is generally where the typical HDRI images I have found fail to work (living in a very flat country, all the nice images with hills / mountains in the background don't really work).

However, won't that look 'weird' with your HDRI sky falling below the horizon?

Re: lightning HDRI vs Sky

Earthworm — Fri, 24 Aug 2018 06:39:57 GMT

You can add a HDRI sky to get realistic lightning, but turn of it's visibility so you can add any background.

Cinerender -> detailed settings -> Enviroment -> Sky Visibility (off)

Re: lightning HDRI vs Sky

Erwin Edel — Fri, 24 Aug 2018 06:57:20 GMT

I tried that a while back, but you need to rotate the sky to match the sun direction, which took a while of figuring out and in the end with our sketchy look for renders I just go with phyiscal renderer sun.

Re: lightning HDRI vs Sky

Anonymous — Fri, 24 Aug 2018 07:14:23 GMT

ejrolon wrote:
Good place to buy high quality HDRI images

https://www.pg-skies.net

Yeah, one of the best, but perhaps for my next project 😉. Every time I am much more fan of CG visualisation. It is, no doubt, the most challenging work in an architecture studio, ( I mean mechanic work, not thinking a project)

Re: lightning HDRI vs Sky

Anonymous — Mon, 27 Aug 2018 14:14:06 GMT

HDR quality is crucial. Those form PG are ok. But for pro CG you need bit more. Also take to the account that HDR render will take more time than Sun. But you can achieve quite decent renders.

Re: lightning HDRI vs Sky

detnies — Wed, 19 Sep 2018 14:23:05 GMT

Hi,

I have some PG-Skies and they work great in renderers such as Vray or Cycles. With these you don't want to use an extra sun since the HDRI contains a very high amount of brightness in certain areas, which will simulate the sun. So in the best of worlds you should be able to use just a plain HDRI and no ArchiCAD sun to illuminate your scene.

However, I'm not able to get good enough results using only a HDRI in Cinerender. Is anyone else succesful using this approach?

Re: lightning HDRI vs Sky

derekjackson — Thu, 20 Sep 2018 11:13:18 GMT

You can always edit the HDRi in Photoshop to increase the sun brightness. There was a tutorial on Ronen Bekerman's blog a while back, and I'm sure there are more online.

We also use VizPeople's HDRIs - they've given us pretty good results once the sun has been brightened.

https://www.viz-people.com/product-category/hdri-skies/hdri/?sidebar=no-sidebar

Re: lightning HDRI vs Sky

detnies — Thu, 20 Sep 2018 20:25:59 GMT

Hmm, that's interesting. I've thought HDRIs are calibrated to have a big enough range between bright and dark so you wouldn't need to do this manually. Perhaps Cinerender has some special way of using HDRIs which differs from other renderers..

Anyway, thanks for the tip. I'll try that!

Re: lightning HDRI vs Sky

derekjackson — Fri, 21 Sep 2018 14:43:24 GMT

We found the same issue using Maxwell, so I don't think it's render specific (unless I was using both wrong!)

In Maxwell I also doubled the intensity of the HDRI's illumination compared to the level needed for background, reflection and refraction.

Re: lightning HDRI vs Sky

detnies — Fri, 28 Sep 2018 09:03:26 GMT

Okey, that's interesting I've never had to do this in Cycles, Vray etc. to achieve desirable results. I'll look into this
Another approach would be to remove the sun completely and use the ArchiCAD sun for direct light. I have some HDRIs setup this way I can try!