HDRI from Max Scene

[jujubee]

Is there any way to create an HDRI from a basic scene in Max? I was curious about this. Perhaps take a dreamscape background- render it in a viewport and do a conversion? Maybe even take a spherical metal ball with high reflectivity- render it out and use this as a 1:1 to be chopped up in HDRShop.

I'm just wondering if there's something exposure-wise that Max is unable to reproduce. If possible, this sounds as if this would be the making of a great plugin...

-jujubee

[flipside]

It's perfectly possible. Create a scene, render it with vray's spherical camera(360°) and save as hdr (you'll need brazils hdr plugin to be able to save as hdr).

[jujubee]

Are you going to be losing out on the f-stops though? That's what makes an HDRI and HDRI.

-juju

[flipside]

If you have a scene with lights and stuff, this high dynamic range is present in your render; From the moment you save as bmp or something, all this info is lost. But if you save as hdr, it gets stored. Max is able to handle high dynamic range.

check this too:
http://www.chaoticdimension.com/foru...pic.php?t=4142

[jujubee]

Hey Flip. Thanks for the info- will come in handy for those hard to get hdri shots. Sounds like it's much easier than having to do it with Terragen. So why do you suppose you don't see as many Max rendered HDRI's floating around the web?

[flipside]

Because the intentional use of hdri's is to capture real life environment lighting to get very natural feel of light and shadows. But for studio lighting setups for example, making an hdri in max is a very good suloution instead of modeling an anvironment yourself everytime (especially for reflection puprposes).

I saw several sites with terragen hdri's, or dreamscape, don't remember anymore...

[jujubee]

You're absolutely correct. I was thinking more along the lines of just being able to quickly turn any panorama (or a dreamscape render with clouds and scattering) into a makeshift HDRI via the environment background. I came across a site earlier that had a ton of amazing hi-res panoramas of cityscapes, and was like hmmm... got the wheels turning a little bit. I was just wondering what these images were missing beyond the f-stop (time based capture.) But you said this can be done in Max- somehow time exposured data is added to calculate luminance values- guess it would be considered photon intensity over distance/time in this particular scenario. You sure you don't need to animate multipliers here? The whole varying of brightness over time is what I thought would make for a good HDRI Max export script.

The one good thing about this (if it truly works properly) is that you don't have to clone out a photographer/tripod, or spend hours trying to stitch together a panorama. And another reason is in case you're looking for a sky scene- airplanes or birds perhaps- that way you dont have to deal with trying to capture a HDRI out of a helicopter. And what if you wanted an ocean scene with nothing around you- this would help. Besides, rendering out of Max should come somewhat closer to mimicking reality than the standard max/vray lights right? Granted it's not 'real', but it's gotta be the next best thing.

-juju[/u]

[flipside]

I think you're confusing some things.

The reason to use f stops in a series of photo's is to capture more of the intensities of the environment. the range of a normal low dynamic range image is only 0-255. So a white wall is as white as a white sky in LDR. When you assemble all these pics in hdr shop, it calculates a hdri images with values that exceed the 0-255 range, and therefore it stores info about very bright pixels like sky, sun, lights, etc...

Now in max, if you setup a scene with for example some bright white cards, with output multipliers above 1, you already have a high dynamic range in your scene because the white pixels of your white cards exceed the 0-255 range. If you would render this scene and save the image as bmp, all the values that exceed 255 will be clamped to 255 and you have a low dynamic range. if you save it as hdr with brazils plugin, the hdr data is stored correctly.

The parameter time is only there in photographing a series of images in real life. If you would take all of your different f stop images at the same time, it would also be good. Or if you have a camera that can capture the hdr values, it's even better and you would also only have to take 1 single pic to have a hdri (and these camera's exist!!).

[jujubee]

Well anyways, if it works it works. Ill have to render out a test scene later to see how it performs.

Now these cameras- do they capture in near 360 degrees without a christmas bulb? A camera must be visible in the scene otheriwse it's not true 360 degrees. Perhaps it creates some sort of clipping path if this is the case. And do they automatically assemble these images into different types of mapping- vertical crosses, etc...? How much do they go for?

Someone out there has to be smart enough to know how to update my Olympus's BIOS to do this (minus the crystal ball)... Any takers?

-juju

[flipside]

I don't remember which camera is able to save as hdr directly. It was expensive for sure... To create panorama's you have different options, just do a search on google.

[jujubee]

I've done several panos using stitch and panoweaver- both very good products from realviz- but man they are time consuming. Plus you often get people walking by looking at you as if you're a weirdo when the see you circling around 360 degrees 3 separate times.

[theo]

expensive indeed..
http://www.spheron.com/

[jujubee]

ok- I can't seem to do a US conversion. But I'm sure a whole system can't be cheap. Btw, I did a google search for HDRI camera and have come up with some amazing results down the trees. Good links to HDRI images/Panoramas that I haven't been able to find elsewhere. Check it out!

http://www.cs.huji.ac.il/%7Edanix/hdr/results.html

[jujubee]

Holy smokes- $50,000!!!!!!

[teabag]

guys do you use max standard free camera for the studio HDRI rendered in max? i am having difficulties with rendering my own studio hdri...

i use standard max camera and set it to spherical with fov 360 in vray rolout.......is that the correct way? cos i am getting really wierd results...

thanks