www.kraytracing.com

Something I've notice, to get nice occlusion shadows I find setting the defuse to around 50-60 works best. Is this normal? Is there any way KRay's defuse model can be the same as LW?

I've downloaded a VRay scene call Cornell:
http://www.chaosgroup.com/stuff/PMapTutorial/
I've ported the scene into LW. After re-adding the lights & setting the surfaces to 50 Diffuse I've got some great results. I had to turn up KRays Photon multiplier to 2 to get the warm colours. The lights still need toying with though.



Shaun.[/img]

What's so different between lightwave's diffuse model and kray's?

50-60 diffuse is a pretty normal value, depending on the material of course.

If you want to match that kray render with the vray one you have in that picture, first you need to fix that pixel aspect ratio problem, then you can play around with tone mapping a bit, you could use a tad higher gamma for example.

AcidArrow wrote:What's so different between lightwave's diffuse model and kray's?

50-60 diffuse is a pretty normal value, depending on the material of course.

If you want to match that kray render with the vray one you have in that picture, first you need to fix that pixel aspect ratio problem, then you can play around with tone mapping a bit, you could use a tad higher gamma for example.

I'm really not that fussed about the pixel aspect, I'm not looking at matching the image 100%. Besides it was 4am when I was working on this.

Hmm okay, up till now most of the surfaces I get or create usually have a value of 100 for the diffuse. LW's default is 100. It's just seems that KRay likes them in the low ranged when compared to LW's & Fprime's render. Thinking about it this might be due to the lighting KRay requires, re the fall-off settings ^2.

Still I'm very happy with the quick results I'm getting from KRay, though I do have a small light leek happening around the bottom of the small wall next to the hoops. Not sure how to cure that.

Rather than play with the gama, I just dropped the lights falloff a little. :0)

Shaun.

Would it be worth posting the full scene here?

Shaun.

Nemesis CGI wrote:Hmm okay, up till now most of the surfaces I get or create usually have a value of 100 for the diffuse. LW's default is 100. It's just seems that KRay likes them in the low ranged when compared to LW's & Fprime's render. Thinking about it this might be due to the lighting KRay requires, re the fall-off settings ^2.

Not sure how LW's model works but when using Kray, if you set diffuse to 100% the surface will reflect all the light that hits it (not a physically realistic scenario, in other words) and if you then add reflection too, the surface will actually generate extra light when hit.

Basic rule of thumb is that diffuse+reflection should always be less than 100% for realistic results - although you can break the rule if you're after special effects.

NB the diffuse value also takes colour into account, so a pure white surface (rgb 255 255 255) with diffuse = 100% will reflect all the light that hits it. A mid grey surface (rgb 128 128 128) with diffuse = 100% will reflect 50% of the light that hits it.

Phil

phile wrote:

Nemesis CGI wrote:Hmm okay, up till now most of the surfaces I get or create usually have a value of 100 for the diffuse. LW's default is 100. It's just seems that KRay likes them in the low ranged when compared to LW's & Fprime's render. Thinking about it this might be due to the lighting KRay requires, re the fall-off settings ^2.

Not sure how LW's model works but when using Kray, if you set diffuse to 100% the surface will reflect all the light that hits it (not a physically realistic scenario, in other words) and if you then add reflection too, the surface will actually generate extra light when hit.

Basic rule of thumb is that diffuse+reflection should always be less than 100% for realistic results - although you can break the rule if you're after special effects.

NB the diffuse value also takes colour into account, so a pure white surface (rgb 255 255 255) with diffuse = 100% will reflect all the light that hits it. A mid grey surface (rgb 128 128 128) with diffuse = 100% will reflect 50% of the light that hits it.

Phil

Cool, I get you. When I first setup that scene the orange wall was bouncing far too much orange back in to the room, making the floor almost orange. Yet at 60% the results were tamer..

Though for the life of me I still can't cure that light leak. Any ideas?

Shaun.

set paths= 1 or 2 on FG tab

Here is a little test with the demo version, and here is the scene with the setup.

Ana028 wrote:Here is a little test with the demo version, and here is the scene with the setup.

Wow that's slow. Glad I have the latest version. :0)

Contact shadows look better, but the over all look is patchy.


Going to try more paths tonight, just got to pop out for a while now.

Shaun.

Well, here's my go - and the scene & object files.

Phil