thanks a lot for the mental ray style ambient light…I’ve wanted this for years.
now i can do instant ambient occlusion with transparencies and conserved diffuse colors…that’s great!
now if only it worked with VRayRT 
Wish I could actually download SP4 so I can see what the difference is between this and a regular sphere or dome light..
The ambient light is brilliant. Very nice for faked gi for moving objects. Thanks for this update. Very easy to set up now.
Vlado, is there a way to get vray dirt to sample the environment ?
Regards,
Mike
:neutral: indeed, env sampling seems to work in only screen space mode 
Not right now; this is best reserved for the dome light (which, in newer builds, will also allow you to set the shadow ray distance).
Best regards,
Vlado
Yes I have full confidence in the upcoming domelight tweaks for optimised rendering (the domelight is allready great), but I also like it quick and dirty :).
Now anyways, the bottomline is, the ambientlight is allready awesome.
as my download is still going on, what does it?
cheers
stefan
I’m a little confused here. At first I thought I could put an environment map in the lightmap slot but that gave odd results, then I put vraydirt in there and it has AO - but what’s the difference between this and the dome light? Is it calculated differently?
domelight is not AO…
with AO you’ll get “illumination” in closed rooms too, like inside a (shelled) box.
It makes every object self illuminated and occlusive at the same time, every surfaces point samples from other areas within the the dirtmap radius.
As I’m in the middle of a project, and so won’t be downloading SP4 yet, could someone tell me what the VRayAmbientLight is/does.
Thanks.
Yes, enlighten us please. 
Marc, are you planning on updating your AO script to include the new ambient light?
Could you dumb that down for me please.
Yes, definitely
Hopefully I can find some time to update it, I also got a lot of feature requests.
I can easily add the new ambient light mode, for preserving diffuse colors and reflection/refraction. Whats not so easy is preserving material options in classic b/w mode, I’ll have to think about that.
Viewport rendering and texture baking would be cool too.
I also started working on some interesting feature to layer/multiply occlusion, which is probably useless, but it looks great (excessive black bleeding overkill).
But the real fun starts when Vlado (hopefully) adds support for dirtmap and ambient light in Vray RT
VRayAmbientLight adds the ability to create an ambient light in VRay, similar to Mental Ray or scanline ambient. Additionally, you can add AO in the form the VRayDirtMap. This is presumably no faster (or slower) than manually adding AO to all your materials, but provides the obvious benefit of a global control.
What seperates it from the VRay Dome Light is that it can use AO, rather than brute-force GI which doesn’t provide the usual benefits of AO (ray distance, etc.)
Please correct me if this explanation is bullshit
isnt real ambient occlusion the calculation to find out whether or not ambient light is reaching a surface? ie: the same stuff as calculating an overcast day? and wouldnt the dirtmap thing be just a fake for ambient occlusion.
isnt real ambient occlusion the calculation to find out whether or not ambient light is reaching a surface? ie: the same stuff as calculating an overcast day? and wouldnt the dirtmap thing be just a fake for ambient occlusion.
Pretty much. But AO indirect lighting is so fast to render . And when you can sample the environment for color, it can look real nice as well. IMHO not as good as GI, but alot of times good enough, especially with moving objects. I would love to see the Vray dirt be able to sample the environment. This is one of the reasons we use MR so much for animation.
It would also be nice to be able to use Vray dirt as a light shader.
Regards,
Mike
Sorry for hijack, but could you pls tell how in short to setup that in MR ?
There are a few ways to do this. The easiest way is to add an ao map to the projection slot of a standard omni light. Make sure that your omni is located at 0 0 0 coordinates. Then drag the ao map to an empty material slot in the mat editor. Change the distance to anthing you want. To sample the environment change the “mode” to 1. It is at 0 by default. Load whatever map you want for the environment. You can also use the background switcher to use a different map for the actual background.
The workflow for Maya is almost the same. If you have any questions about the other ways of doing this, just ask.
BTW, there is a simple tutorial for using the ao map as a light shader on my blog.
http://mikebracken.cgsociety.org/blog/
Regards,
Mike
This was planned, unfortunately it didn’t make it into SP4, but will be added for the next update.
Best regards,
Vlado