real sun/skylight

[percydaman]

my little attempt. Some photoshop adjustments. I can't, however, share rendertimes as this is a beta.

[Pixelperfectg]

apparently people are trying to recreate the same thing with mental ray too.

Indeed I was trying to match the Maxwell lighting with MR too. I took one of my MR dome-rig scenes and converted it over to VRay. I like the result, eventhough I put a little too much Photoshop sharpen on this one


Jeff

[BBullo]

Percy, you used a Vray Beta version?

If you did use Vray tell us about you light set up. Direct Light or IES for the sun, and any exposre control you used.

thx

[percydaman]

i just used the public beta. Direct light for the sun and just some colormapping. No max exposure control.

[Trapezium]

Nice tests guys

I set an animation to render at work over the weekend and I'll post it tomorrow if it looks any good..

Pixelperfectg: Any luck recreating that look with VRay?

--Jon

[Pixelperfectg]

Well, I guess not....The render I posted above is a Vray render.

[Trapezium]

Whoops, my browser was truncating "VRay" at the end of that first sentence. Nice work Would you mind explaining your setup a little more in depth and maybe post a before and after PS?

--Jon

[Pixelperfectg]

No problems. Here's a link to my Mental Ray skydome tutorial.
http://www.jeffpatton.net/Tips/Sky-dome.htm

I kept the dome and single direct light from this setup. I used the gradient ramp in a VRayLightMtl as the texture map. Then applied that to the dome. The direct light has a deep yellow-orange color (255,190,106) and a multiplier of 1.25 . I excluded the dome from this light.

I used Quasi-Monte Carlo for both the Primary and Secondary bounces. Primary has a multiplier of 7.0, secondary used .5

And that's all that I changed from the default VRay settings.

And here's the original unmodified render:


I posted a scene in that MR thread at CGtalk if you want to test the same setup.

[richard_rosenman]

Hey guys;

The first image is BBullo's scene rendered with Maxwell Render.



The second image is BBullo's scene rendered with VRay 1.4570.



Both have minor Photoshop adjustments - primarily level changes and a slight glow. Both have had identical corrections - (ie. same level amounts, same diffuse glows, etc.)

As you can see, it is possible to recreate a similar render to Maxwell. Most notably, there is still some blue indirect light lacking in the VRay render in some areas. It should be noted, however, that while it is very easy to recreate the lighting of an existing image, it is much more challenging to develop this type of lighting from scratch. But the point is that it can be done if one has a good eye for lighting.

Best regards,
-Richard

[alkis]

hi all
i ve been testing the ies+log exp. control method in some of my scenes and it works very well.
however i came across a quite serious problem
the enviroment HDR of my scene is not reflected in any of the reflective surfaces of the model. This happens when the HDR is placed in max s enviroment slot or vray s or both.
the problem exists regardles of the method used (QMC,lightmap etc.)
any ideas would be greatly appreciated
kind regards
alkis

[themaxxer]

for me, the biggest difference between the two images from richard, is the indirect illumination from the sun on the other wall!
this is because maxwell does know the "strength" of the sun, but vray doesn't.
with vray we always set a direct light or something similar for the sun, with more or less multiplier, but never with 60000 lux. it's difficult to find the right amount of light for the sky and the sun.
I think we would get better results with the linear color mapping.
and vray schould "see" the sun, this would be great, the direct light should be visible to vray.

but we have dreamscape to simulate this.

best regards
themaxxer

[dennis]

the hdr not having strenght enough could be because you have to set the physical scale ( exposure setup ) to match the light with the most intensity in this case the sun.
play around with it untill you get a good balance, note this will also multiply the vray environment light so this should be lowered.

what it does is multiply everything but the photometric lights ( including reflections ) or so i remember from the docs.

Now a question. I read that you, samuel had problems with the aliasing in the unclamped areas when working in DF, and so do i.
I dont know if this is how its supposed to be and one just have to add some layer ontop or what.
any insight would be appriciated.

[themaxxer]

dennis

maybe this could help you: http://www.chaoticdimension.com/foru...268&highlight=

best regards
themaxxer

[plastic_]

hey Richard,

great comparsion...now i have a load of questions

how did you recreate the skylight with vray? spherical gradient environment? hemispherical skydome with a vray lightmaterial, as Jeff used?

did you use logarithmic exposure correction?

how many bounces for the vray render?

[plastic_]

for me, the biggest difference between the two images from richard, is the indirect illumination from the sun on the other wall!
this is because maxwell does know the "strength" of the sun, but vray doesn't.

you're right, it's the obvious difference.
maybe what we need is a GI output multiplyer in the vray light, as seen in the vraymat wrapper.