HDRi Background Settings in Maxwell.

Aidus · 25 Feb 2009, 06:48

Hi!
How can I improve that background [sky] image?
Render @ ~2500x1111 but hdri resolution is ~1024x....

brodie · 25 Feb 2009, 19:25

I've had the same issue (in Maxwell). Basically what I found out is that many times places will provide a high quality HDRI image and a low quality one. The low quality one is really just for the Illumination channel since you don't need much detail for that and it makes things faster. Then you use the high quality one for your background and reflections (could do low quality for reflections too if you don't have mirrored glass or anything like that).

The 10 or so HDRI images that come with Maxwell all seem to be the low quality version . Not sure if your sky was one of those (I don't recognize it but I usually just stick with RADSKY017 or something like that) but that seems to be the issue.

I don't know if I have the best solution yet (other than getting a high quality HDRI), but here are some work arounds I've played with. If you ran a materialID or objectID you can select just the sky portion in Photoshop and do a diagonal motion blur. This gets rid of the pixelization and gives the clouds some 'movement' but unfortunately it looks like airbrushed clouds so you loose some realism (an improvement on that is to duplicate the cloud layer before editing motion blur the top layer and then turn the opacity down a bit to reveal some of the detail underneath but not enough to show the pixelization).

I've also created my own background by just taking a big sky image in Photoshop and saving it as an EXR image. I used it for reflections and checked the box to map the image to the background (can't recall exactly what maxwell calls it) so it's just a flat background image like a SU watermark.

Lately, though I've been using an HDRI for the reflections and just photoshopping in a sky later.

Let me know if you figure out anything else on this issue.

-Brodie

brodie · 25 Feb 2009, 19:26

like that tree on the left side btw

Aidus · 26 Feb 2009, 08:23

Thanks brodie for replay.
Actually now I'm using different method. Rendering with alpha channel and then use it with photoshop.
Here is result. Different view but the same model rendered with alpha.

brodie · 26 Feb 2009, 17:30

Looks excellent. BTW, if you don't already have it here's a link to a photoshop action from Maxwell's Think website. You open up the color image and the alpha in Photoshop and it deletes the background from your color image for you by using your alpha.

http://think.maxwellrender.com/maxwell_alpha_photoshop_action-110.html

Aidus · 26 Feb 2009, 21:06

Thanks Brodie! I knov that photoshop action but i better do that alpha stuff by myself because that's how I'm learning all this IT CG an other stuff Learning never stops
Btw I did not understand how that action is working because when I run it I had some sort of errors

PS. Soon I will post my final renders and screens from su of this model.

brodie · 27 Feb 2009, 13:45

Great look forward to it.

Your sig shows that your e6750 is at 3.2GHz. Is that overclocked or is that what it runs out of box? I finally got my home computer built (well rebuilt after I screwed up the bios) and I'm thinking of overclocking my e8400 which is 3.0 GHz stock.

-Brodie

Aidus · 27 Feb 2009, 13:54

Yes it's overclocked. Core 2 overclocking abilities ar really great.

brodie · 27 Feb 2009, 17:28

that's what I've heard. How did you overclock it? I've never really gotten into processor overclocking before.

-brodie

Aidus · 28 Feb 2009, 12:04

Brodie the best thing You can do is search OC and Hardware forums or simply google. Write your mobo and cpu model in search field and that's it. There are lots of info and tutorials about how to do that OC process depends on Your mobo and processor type generally. One thing that I can tell sure is that values in bios You must rise very slowly especially if You doing it in first time