View Full Version : Use other background with physical sky

11 November 2009, 06:08 PM
Hi there;

I was trying to use other background with physical sky with no luck...

I want to use an IBL node with it, but if I connect it to the mental ray environment slot of the camera, nothing happens and some errors pop up in the script editor.

Any ideas?.


11 November 2009, 11:30 AM
Hi, I use this very simple and effective method:
On environment slot on your camera plug mip_rayswitch node. In mip_rayswitch plug mia_physicalsky into finalgather (and photon if you use it). In all other slots plug mib_lookup_spherical with your longitude/lattitude texture of choice. You will have to gamma corect it of course and multiply its brightness.

Have fun!

11 November 2009, 12:34 PM
So is there no chance to use IBL?, only a spherical projection?.

11 November 2009, 01:02 PM
I tried also that, but didnt find right solution.
But anyway, why would you use both physical sky and IBL? IBL has easier control over texture maybe...

11 November 2009, 12:11 PM
Well, it's just a matter of having more possibilities..., more ways to do things mean less chances to get lost because one of them doesn't work or it's buggy.

11 November 2009, 12:50 AM
I have a tendency to do things that "just get the job done", when I'm working on a deadline and physical accuracy isn't so important. I'd LOVE to be able to plop in files into the MR environment and just go to town with those, but it's never been that easy for me.

So sometimes I just make a huge sphere around my scene and drop a file texture in, connect it to Ambient and/or Incandescence, and see how FG handles it. If it doesn't generate enough light, I just crank up the FG scale. Not remotely "accurate", but sometimes it can make a huge difference, in both realism and speed.

Another option, especially for indoor scenes with windows or open doors, is to just make an IBL "card". Simple poly-plane, scaled and mapped in the same way as above, with a file texture driving the FG via Ambient Color and/or Incandescence slots. Sometimes this works well. Other times, it is horrible, and still other times the FG lighting looks fine but the image itself is horrible when rendered in the scene. So, off goes Primary Visibility, and there you go.

Just some ideas. I'd love to have more control over the MR environment itself too, but never took a lot of time to learn about it.

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11 November 2009, 12:50 AM
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