Mental Ray Skydome tutorial


I’ve added a quick tutorial for making a realistic skylight dome to my website. Here’s a few renders from the setup:

I would normally just throw the scene out there and let you guys tear it apart. However I’ve received a good bit of email from people wanting an explanation instead. Sooo, I’m trying to do just that. However with limited time to dedicate to this, the info I threw together might be too scattered? If so, let me know. I just bascially wrote down what was in my head.

Here’s a link to the tutorial:



Thanks a lot :thumbsup:

Very interesting read. I wondered about this extremly low FG samples.
I will do some experiments too.
What was your rendering time?
I always used glow instead of glare on my skysphere. Does it make
a different?

all the best

edit: my Browser Opera shows parts of the text over the images. It’s still readable.
Just wanted to let you know.


The rendering time was a bit slow with the small FG radius. It was around 4 minutes for a single frame. That can be improved on my increasing the minimum FG radius…but then the samples will have to be increased too…but I’m sure there’s probably a happy medium there somewhere. :shrug:

I didn’t really use the glare for the dome, it was to make the sun highlights a touch brighter where needed. Did you mean is there a difference between the glow and output shader? From what tests I’ve made, I don’t see any difference in output from either.

Thanks for the info about Opera. Unfortunately, I don’t know what to do about it. I stink at putting web pages together…Terribly sorry about that.


nice tutorial :slight_smile:
I’m going to experiment a bit with it… thanks

btw. firefox has the same problem with the text over the images, but you can still read it fine.


great as always jeff !

you should sell your tutorials to discreet …

thanks a lot, oliver


4mins is still fast compared to my render times.
Normaly I switch off the radius settings and increase the FGsamples until it looks good.
I should take some time for further experiments.

I meant the difference between using glow/glare for the dome. I don’t know if it works if you use glare for the dome (I never tried it) But I would be interested to know how you control sun highlights (especialy “where its needed”)

here’s a best of “worst parts” :smiley:
It’s not that a problem

I have to agree with panrok. You should get a award, just because so many artists (including me) make use of your experiments and results :applause: :applause: …applause and standing ovations
Thanks a lot :thumbsup:

all the best
florian (including 6beer)


Well that sucks about the text messing up. I’ll have to dedicate some time to learning better html I suppose to try and make a page that works for as many as possible.

“great as always jeff !”

“You should get a award, just because so many artists (including me) make use of your experiments and results”

Those nice comments are rewarding to me…but thanks you guys.


Just give it a empty line. I know of lots of weird sites in Opera that are based on html.
Maybe it’s more a opera problem. Beside that, it’s fantastic.

flo (including 8)


Here’s another test render using the skydome & one MR spotlight. I’m just trying to recreate the feel of these wonderful Maxwell test renders on RichardRosenman’s website (

Here’s my render (render time about 20 minutes):


This Maxwell renderer seems to be just as cool as the greeble pugin. I’ve also fallen over this site today:

Can you do me the favour and put the max file of your last scene online?
I still can’t believe that low radius settings wins against lots of FG-samples (without using radius) :wink:



Fantastic info Jeff! I am going to have a run at this stuff myself, just finishing up a project I’ve been working on. Thanks for sharing the info, much appreciated!



florian - I’ve been trying to conserve space on my server (starting to get full and I don’t want to have to pay more to increase the space). However, others have asked for this scene too, so I guess it would be beneficial if I post it. So, here’s the file:
Download Scene
I’ve left the DOF enabled, so you’ll probably want to turn that off to speed the render up.
I forgot which frame I was at when I made the render. Since I’ve animated the skydome and sunlight source the scene opens up at frame0 (the light source will be low in the sky). So, I think I was around frame 45 or so when I made the render above.

Loran - If your following this thread, I modified the scene above and created a more enclosed object for the test. Is this closer to the test you wanted to see?

Obviously I used some low settings. I was mainly focused on the amount of light and not the details though. I should’ve turned off the DOF, but I forgot.


Thanks a lot :thumbsup:

I’m looking forward to take a look at your settings.
I’ve done some tests with my own scene too. Normaly I control the power of GI with the “decay” level. But if I render that scene with radius enabled, my skylight looses influence and the result looks totally different than the pure FG version. Also bump mapping behaves different.
Ok…I guess there are a few reasons to use a dome.

It doesn’t really matter what frame number you used. I just need something with the right settings I can learn from. There must be something I completly misunderstood…or never heard of :rolleyes:

time for testing…


great stuff Jeff - ill look forward to dissecting the scene! thanks a lot :applause:


Thanks Jeff! You really are the Mental Ray Master! haha :thumbsup: thanks a lot!!!


Jeff, you are a tremendous help to those of us trying to work with Mental Ray. Kudos to you, and I hope I can return the favor.

Thanks -


well I have been doing mental ray exterior renders for a while now,
so Loran, it can be done … just take a look in attachment

moslty the same workflow like in jeff’s tutorial
one flipped sphere with glow and one mr area spot for sun (casts also the photons)

I always try to achieve a good base using only photons (no Fg) then just use a tiny bit Fg (not more then 200-500) to get rid of last splotches
but more important to have a skylight effect from the sphere added to the spot-sun

I can only say that workflow will reduce rendertimes enormously
if you rely only on fgather to get a good rendering, you will need 2000 or more fg and the rendertimes take forever

never had to use the radius min/max in fg like jeff is using alot, it’s fast and clean enough for now, but i will try to improve myself with that when i can find some free time …


Same concept except using VRay this time:

I’ll set one up in Brazil R/S some time too.


Thanks for the tutorial BTW very helpful…

I have one question though… I can’t see my dome texture in the viewport… Eve though it’s working in the render. All I can see is a black texture on the dome now… How do I view the mental ray texture in the viewport.?


Yeah great stuff Jeff, really useful to a newbie like myself.


Quick note, I’ve noticed people keep mentioning the glow (lume) shader to be added to the surface of the sphere (skydome), yet in the tutorial you use an output with a gradient colour mask in the mental ray surface parameters.

Which works best or do you people mix them or what?