 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Thanks Christian. Very comprehensive.
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
scott <sco### [at] scott com> wrote:
> I've created a macro called SkySim (I'll post it in p.b.s-f once I've
> tidied it up and added comments) that creates a realistic looking sky
> pigment in a sky_sphere based on the sun position and the "haziness" of
> the sky.
Very nice. I'll definitely be using this!
Bill
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Thomas de Groot <tho### [at] degrootorg> wrote:
> Question:
>
> For the visible Sun, you give: #local SunRadius = vlength(sp)/214.8;
>
> I seem to remember that Cousin Ricky evaluated the apparent size of the
> Sun as to be twice as much, i.e.: #local SunRadius = vlength(sp)*2/214.8;
He is correct. The formula you attribute to me is for the /diameter/ of the
Sun, not the radius. (References to celestial objects tend to give diameters
instead of radii. Another possibility is that the original conversation was
about area_lights.)
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 9-6-2013 19:26, Cousin Ricky wrote:
> He is correct. The formula you attribute to me is for the /diameter/ of the
> Sun, not the radius. (References to celestial objects tend to give diameters
> instead of radii. Another possibility is that the original conversation was
> about area_lights.)
>
I stand corrected! The original discussion was /indeed/ about area lights.
I mixed up radius and diameter subsequently.
How little things may wreak havoc in the celestial clockwork ;-)
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I wonder at your scene settings.
With you test scene, I get the following image. Sun at 12:00 hours. Way
too dark overall.
Using for all my scenes version 3.7RC7, with assumed_gamma=1 and
Display_Gamma=sRGB.
Thomas
Post a reply to this message
Attachments:
Download 'skysimtestground.png' (148 KB)
Preview of image 'skysimtestground.png'
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> I wonder at your scene settings.
>
> With you test scene, I get the following image. Sun at 12:00 hours. Way
> too dark overall.
You can adjust the EXP variable in the test scene to control the
brightness of the sky (it controls how the physical brightness values
calculated are converted to POV units). Try increasing it from 4e-5 to
6e-5 or even higher.
I have no idea what the bright yellow patches on the ground are - I
didn't get those on mine???
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 17-6-2013 11:34, scott wrote:
> You can adjust the EXP variable in the test scene to control the
> brightness of the sky (it controls how the physical brightness values
> calculated are converted to POV units). Try increasing it from 4e-5 to
> 6e-5 or even higher.
Yes I did that indeed, but somehow the scene never comes close to the
aspect of a regular light and sky_sphere.
> I have no idea what the bright yellow patches on the ground are - I
> didn't get those on mine???
I added radiosity, and they seem to come from that. Without radiosity
the landscape remains totally dark whatever the value for EXP and the
hour of the day.
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I think I found the culprit: Your original SunPos() is divided by 1000!
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> You can adjust the EXP variable in the test scene to control the
>> brightness of the sky (it controls how the physical brightness values
>> calculated are converted to POV units). Try increasing it from 4e-5 to
>> 6e-5 or even higher.
>
> Yes I did that indeed, but somehow the scene never comes close to the
> aspect of a regular light and sky_sphere.
It looks like it's because the sun is so bright and so small, the
radiosity algorithm won't pick it up very often. This would explain the
bright yellow patches, they're radiosity samples that just happened to
pick up the sun - most of the samples didn't. I'm not experienced enough
with radiosity to know a way around this (I use mcpov for most renders,
which allows for such small very bright objects ok).
Could you ever get a similar scene with a realistically sized and bright
sun to render with radiosity corerctly? The pigment of the sky_sphere
should only make a very minor difference when a bright sun is in the sky.
> I added radiosity, and they seem to come from that. Without radiosity
> the landscape remains totally dark whatever the value for EXP and the
> hour of the day.
There was a light_source in my demo scene file I posted, that should
illuminate the ground - unless you've uncommented the sun sphere that
happens to be in exactly the same place :-)
> I think I found the culprit: Your original SunPos() is divided by 1000!
That shouldn't make a difference, because the sun radius is determined
from the distance. The reason I did that is because SunPos.inc returns a
massive distance for the sun vector which causes problems in some
scenes, in reality it only needs to be a few orders of magnitude further
away than everything else in your scene.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 17-6-2013 16:21, scott wrote:
> That shouldn't make a difference, because the sun radius is determined
> from the distance. The reason I did that is because SunPos.inc returns a
> massive distance for the sun vector which causes problems in some
> scenes, in reality it only needs to be a few orders of magnitude further
> away than everything else in your scene.
>
And yet, *that* is exactly the trouble maker. Without, the scene renders
perfectly, like the example (with radiosity added again) shows. Also in
any other of my scenes the results are correct. Exp at 4e-5 again here.
Thomas
Post a reply to this message
Attachments:
Download 'skysimtestground.png' (160 KB)
Preview of image 'skysimtestground.png'
|
|
| |
| |
|
|
|
|
| |
