Float like a floating point image, sting like a bee

[joconnell]

Heya Folks,

I wrote a quick thingie on floating point images a while back on the forum to deal with why anti aliasing was bad on unclamped images but wanted to expand it into a bigger article on floating point images and workflow - I got around to doing that and you can find it up on http://www.joconnell.com - So there.

[vlado]

By the way, the exrviewer for the new OpenEXR (1.4) can add bloom effects to the displayed image to deal with antialiasing on bright objects and to simulate the workings of photographic film. It seemed to do this quite effectively (if a bit slowly) and the results are very nice.

Best regards,
Vlado

[nvanherpt]

cheers joconnell, nicely written. so float renders are as useful as RAW files from a digital camera then. this just confirms that i should head out on the linear workflow approach.

shame photoshop isn't as flexible.

[joconnell]

Cheers for that Vlado - I'll be sure to check that out. Yeah Nik you're right - it's not even tied into lwf, just gives you a few more options in post where things move a little faster. You're right about photoshop too, I'd say when they wrote the ps engine they wouldnt have even considered hdri or floating point (Shake is the first thing I can remember that made floating point popular) so its not the best thing for them.Another company makes a program called photogenics that allows you to paint in hdr so it may be a better option. I'm sure its the same situation as max though where they gone so far in development that it'd take a major overhaul to include full support and they really don't want to spend the money or dev time.[/url]

[nvanherpt]

thanks for the photogenics link

[panthon]

Very interesting reading joconnell. It could be cool to have a new vray render element, VrayLightSelect element, which would let u access all light individually to tweak their intensity. I am thinking of something similar to vraymtlselect but with lights...what do u think?

[re:FORM]

By the way, the exrviewer for the new OpenEXR (1.4) can add bloom effects to the displayed image to deal with antialiasing on bright objects and to simulate the workings of photographic film. It seemed to do this quite effectively (if a bit slowly) and the results are very nice.

Best regards,
Vlado

Can you tell me a little more about how to do this? I downloaded the new openEXR but the commandline interface is a little daunting...

[joconnell]

Very interesting reading joconnell. It could be cool to have a new vray render element, VrayLightSelect element, which would let u access all light individually to tweak their intensity. I am thinking of something similar to vraymtlselect but with lights...what do u think?

That sounds like it'd be far more useful than a lot of elements - the mtl select channel is fantastic for sending elements to flame and the such but I could see this being far more useful on a day to day basis - I'd imagine it'd end up with huge file sizes but it'd be worth it.

[vlado]

This is possible only for the direct component of the lighting. Splitting the indirect part as well (e.g. the GI) is not currently possible. For example, the irradiance map stores the combined contribution from the GI of all lights, and this cannot be later decomposed into the original components. I am not sure how useful only the direct component can be.

Best regards,
Vlado

[panthon]

Besides, I am not sure about how reflection channel would deal with light changes. Probably the whole thing is more technically challenging than u can imagine at first sight.
Some months ago i watched a video about lighting in Pixar's Cars, and they managed to create a somewhat realtime lighting engine which helped them to place lights in space and tweak intensities. I cant find that video but i have found this other one:

http://www.vidimce.org/publications/lpics/

Take a look!

[Da_elf]

i just wish i could find a tutorial on how to use the coverage channel for things like DOf, motion blur etc

[ene.xis]

i second that!

[panthon]

i just wish i could find a tutorial on how to use the coverage channel for things like DOf, motion blur etc

From my experience, RPF DOF AND Motion Blur, either with coverage or without it, suck. The information stored inside vray channels is still valuable, but the best results are obtained using 3rd party plugins for both DOF and MB.

[Da_elf]

still. it doesnt hurt to know something.

[joconnell]

Absolutely - I'm gonna look at the latest reelsmart motion blur since it supports float and rendered motion vectors, I'm not gonna hold my breath for coverage based dof though.