Sun showing through objects

[PeanutMocha]

I'm rendering a scene with the sun 1.5 degrees above the horizon.  However, it looks like it should have been partially obscured by trees (TGO's) on a hill.  The sun disk doesn't seem to be obscured much, if at all.  Is there anything I can change in the render settings to make the sun disk appear more realistic?

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[Kadri]

Did you look at the Atmosphere node "Receive shadows from surface" setting?
Render time will be longer. The fastest would be to make a crop render near the sun.

[Simius Strabus]

I've had some poor results with cropped renders in the past. Somehow the colors are not the same. Not sure why/how that happened.

[Kadri]

I think it is because of the GI calculation .
I would basically take a bigger crop and adjust it a little .

The last additions with GI caching might be a help with such problems.
If you save your GI calculation before your first render.
Although because your Sun will look different you could get still a different look not sure.

The advanced render settings might be helpful too.

I had not such a problem so just guessing 

[PeanutMocha]

Receive Shadows from Surface was not checked.

Do I just need to check it for the atmosphere, or also for the cloud layers?

[Upon Infinity]

Should just be the atmosphere.

[Kadri]

Yes only atmosphere is enough.

The cloud setting is more about getting shadows from other surfaces on clouds.
As a mountain that can have his shadow on clouds below.

[JasonA]

Actually Im finding that I have this issue too. 

I'm using DEM derived ter files in my scene and when I turn the camera to face the rising sun with a mountain in the way, the sun glow is in front of the mountain.   

*edit

I wondered if maybe it was non-native objects that had the problem but I tried a blank scene, created a default heightfield and pointed the camera to the sun with a really low elevation angle.  Sun glow is in front of the heightfield.

It'd be good if anyone else can confirm this.

[Kadri]

Did you tried what i said in the first post in this thread , Jason ?
It is not a bug.
It is an option because (probably!) when that setting is checked render time gets longer .

If your problem is related to that setting of course .

[JasonA]

ah yes Kadri, sorry I didnt try it.  I saw the comment and glossed over it because I didnt think the sun was the atmosphere.  But Youre right that fixed it.  Cheers bro

[Kadri]

No problem 

[Kadri]

Actually Jason you reminded me that i wanted to say something about this setting.
It is not a major problem but anyway...
I do not know why Matt put that setting in the atmosphere node.
Maybe because it is related to that node ,
but i always felt that the render node would be a better place to put that option.

It feels more intuitive for me to see it there.
Not sure what you guys here think about this?

[Tangled-Universe]

Isn't it logical to have it either in the clouds or atmosphere?

The option says "receive shadows from surfaces" which means that *this* atmosphere element will receive shadows from surfaces.
The same goes for clouds. You can specify the need for calculating shadows from surfaces *per* cloud layer.
Clouds lower than mountain tops (for instance) would require "recieve shadows from surfaces" but the cloud layer up above in the sky wouldn't.

If you would have this setting in the rendernode then it would apply to all atmosphere or cloud elements.

Otherwise the render dialogue would need to get a dynamic update for the amount of atmosphere/cloud nodes in the network and it would also need to deal with the ones which are really active in the network node or just being passively disconnected by the user.

I can see your point, a bit, since it's related to rendering, but so are many other settings in the atmosphere or cloud node related to rendering and thus it's in the right place in my opinion.

Cheers,
Martin

[Kadri]

Yes you have a point too Martin , but if you think about the sentence " receive shadow from surfaces"
it is hard to think about the Sun shining through the ground!
I would look first at the Render node or the Sun node but atmosphere wouldn't my first bet about this.

Wish there were two settings one for really only " receive shadow from surfaces" for the atmosphere
and one "Sun behind objects" kind of setting .
Of course this might have not any meaning from the render engine side, i don't know!

[Tangled-Universe]

Yes you have a point too Martin , but if you think about the sentence " receive shadow from surfaces"
it is hard to think about the Sun shining through the ground!
I would look first at the Render node or the Sun node but atmosphere wouldn't my first bet about this.

Wish there were two settings one for really only " receive shadow from surfaces" for the atmosphere
and one "Sun behind objects" kind of setting .
Of course this might have not any meaning from the render engine side, i don't know!

I disagree.

The sun is a light source and the medium where the light propagates through is the atmosphere.
Shadows are cast into the atmosphere or in other words there's less light behind areas which obstruct direct light.
That's all happening in the atmosphere and the sun has nothing to do with that other than emitting light.

If I think about "receive shadow from surfaces" in the atmosphere node then I realize that it is not being calculated if it's disabled.
So what do I expect when the sun is behind terrain and the atmosphere is told to not calculate the shadows from surfaces?
I would expect that the terrain wouldn't not cast a shadow and that the light from the sun still should be visible. If it wasn't then it was casting a shadow

By default the atmosphere does not receive shadows from surfaces. Why? Because in the vast majority of situations the sun is not behind/below the terrain and thus that is default.
What you describe is the symptom, not what's causing it. Therefore there shouldn't be a "Sun behind objects" option, or better said, there can't be a "Sun behind objects" option (at the moment), because the calculations required is the one provided by the "receive shadow from surfaces" option.