MR Physical Sun not visible

[jasonbabska]

Hello All,

For some reason the sun is not visible in the sky when i use MR Physical Sun/Sky.

Is there a setting that specifically turns on or off the sun?

I must be missing something, the sky, horizon and shadows all render fine but no sun in the sky. Any advice would be greatly appreciated.

Thanks so much!

[SgWRX]

jason, the sun is turned on by default. you will have to set a fairly large sun distance or "orbital scale". like a mile or km. then position your camera so you can see it. then just render and you'll start to get a feel for where the sun shows up.

 

also, you can turn on use background image by hitting "alt +b" on your keyboard, and make sure to go into "realistic" viewport mode. you may have to hit "ctrl+L" to turn on viewport lighting via the mr sun/sky. "realistic" will also roughly show exposure settings and vignetting if you have that set.

[jasonbabska]

Hello,

Thanks for the reply! I am realizing now that it may have been an out of scale test model which threw things off not allowing the sun to be visible.

I am curious though just as an aside, is it possible to get the sun to reflect off of glass such as a window for architectural rendering purposes?

I have tried glass and even mirror materials but I cannot seem to get that specular reflection of the sun on my exterior renderings.

Thanks Again!

[Nicolai Bongard]

It has been a while since i did anything with mental ray, but from what i remember the sun can be enabled/disabled on the "sky material"? So in your environment slot there should be an mr sky of some sort, try to drag that (instance) into your material editor and see if the sun is enabled or not?

[SgWRX]

yes there's a mrphysical sky which ends up automatically (if you select yes at the prompt upon creating the mentalray daylight system) as the background. you can instance that into the material editor and tweak settings.

 

you should be able to get the sun reflected in the windows of a building or whatever by playing around with the time of day and the "north direction" of the sun/sky parameters.

 

and in fact you can change the size of the sun disc that appears in the rendered sky inside that mrphysical sky mentioned above. realistic is 1 but i think the default settting is 4.

[jasonbabska]

Thanks again guys,

I have tried some of the options you both suggested. For whatever reason in some models the sun is there and in others its just not. It makes sense that it has to do with the orbital scale but so far I can't figure out the precise control. I am making the transition from Form Z to 3ds max and maybe I just need to keep working with Max/Mental Ray to get good with it.

[SgWRX]

well, the orbital scale should only be for helping to place it in the viewport. if it's really far away, then it's easier to track down in the viewport due to the angle you're looking for when you orbit around the viewport.

 

go into the "environment & effects" - is the mrphysical sky listed as the background?

[SgWRX]

so here's what i did in a new scene.

 

1. created the teapot and plane (plane is 4ftx4ft).

2. went to create menu > lights > daylight system

3. clicked and dragged in the viewport near the plane to create a compass (n,s,e,w)

4. release the mouse button and got a warning that said "you are creating a mr sky"... it's recommeneded to also add a mr physical sky environment map... clicked Yes.

5. then i moved the mouse without holding any buttons down and that dragged out a line from the compass to a "light head" which is a sky and sun

6. it was quite close to the teapot as you can see, so i had to swing around in the viewport (orbit) in order to find it. this is the picture "underground", beneath the teapot.

7. next i selected the mrsun/sky and went into the "setup" and changed the time of day to someething late like 1800hrs or 6pm. this drops the sun down to the horizon and shows the relationship between the "light head" and the sun disc on the horizon.

 

does that help?

 

EDIT: forgot to say after i created the sun/sky, i hit ALT +B on the keybaord and for the background selected "use environment background"

[Nicolai Bongard]

Another thing that might help you to get the sun into view is to increase the field of view on your camera. When you select your camera you should see a sortof cone shape that basically shows you how wide you can "see" through your camera. If you widen the fov you should get a wider cone, thus making it easyer to capture the sun in your picture.