Does the new IBL work with the useBackground-shader? I can´t seem to get any shadows on there.
edit: ok, so the usebackground only catches normal shadows? How would I go about to get the occlusion/shadows from the IBL onto it? Or should I just use a normal occlusion pass?
You might want to try the mip_matteshadow from the production shaders. I do have some strange issues with the built-in IBL if I use it in the beauty, but it can give you occlusion, etc in separate passes.
Interesting. Thanks, I will look into it. Funny how most of my MR questions lead to djx blog 
btw, what kind of issues do you have? something that renders the beauty unusable?
Sometimes the IBL will reveal the geometry of the matteshadow object and I can’t seem to make it go away every time.
Is the new IBL supposed to work witthout major bugs with mia material transparency?
the reason why I am asking is that I´m working on a pretty complex scene, and was about to add some glasbottles when I noticed that the transperency had no effect. Checking all ray-values, raytracer in the featurestab, checking every possible thing I could think of, turning all IBL-values to high (like transparent shadows and stuff), but the transparency was still not showing. Then I deleted my IBL-setup, and it worked.
I suggest to you to write here:
http://forum.mentalimages.com/forumdisplay.php?82-mental-ray-Maya
Maybe mental images start with some features that work for user.
What IBL setup were you using?
Remember the Maya IBL is an Autodesk feature.
The native IBL feature can use that but it can also use a regular lookup sphere instead. (Pretty much an environment attached to the camera.)
I created a regular IBL setup from render settings, attached my hdr, then used the mr string option script to turn on the hidden IBL features. That´s it. If I delete the ibl-node and add a point light, I can see the transparency work.
I just realised I´ve missed to check something very obvious, create a new scene and create a ibl-setup and a transparent material to see if it is the scene or the ibl that is causing trouble. Will do that later today.
But I guess it must be my scene somehow, an issue like the new ibl not working with transparency surley wouldn´t go unnoticed.
How can you control the amount of light ? Through the hdr’s exposure ( in photoshop )?
Try boosting the color gain of the HDRI a bit. The default is one but it can be pushed up.
The builtin IBL has a string option for “scale” this is the amount of light emitted basically. It defaults to 1.0 naturally but you can make it brighter by increasing the value.
environment lighting scale
1.0
scalar
Then change it to whatever. Keep in mind that if it’s too bright, Maya implemented materials lighting needs reduced by 1/pi
Otherwise you can crank it to whatever you need.
Maya implemented materials would be the default maya materials, or mr for maya materials ? I’ve read this 1/pi “thing”, but i didn’t understood properly what it means, and where to apply 1/pi. At the light intensity? At the material 's diffuse multiplier? Or on the maya shader’s irradiance attribute?
Thank you so much !
It means anything except a BSDF material (unexposed but possible to use or MetaSL) has a different lighting convention.
So the intensity of your light gets multiplied by the inverse of pi.
It makes a difference if it’s too bright given your scene HDRI or if you mix materials it can get weird.
Most of that you don’t need to know, just the overly bright part if it happens for unknown reasons.
The lighting cache is designed more for interactive purposes, I would not use it for now.