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On 8/6/2018 5:15 PM, Mike Horvath wrote:
> An old scene, but I've been sprucing it up in preparation toward
> uploading it to the Object Collection. I can't remember if it's to
> proper scale however. Also I'm thinking there may be a little too much
> cloud cover.
>
>
> Mike
Also, due to the sun being an area light, the unlit regions are much too
small.
Mike
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On 06/08/2018 22:34, Mike Horvath wrote:
> On 8/6/2018 5:15 PM, Mike Horvath wrote:
>> An old scene, but I've been sprucing it up in preparation toward
>> uploading it to the Object Collection. I can't remember if it's to
>> proper scale however. Also I'm thinking there may be a little too much
>> cloud cover.
>>
>>
>> Mike
>
>
> Also, due to the sun being an area light, the unlit regions are much too
> small.
>
>
I got similar results when I tried it. I suspect Larry Niven got his
maths wrong. I had to move the shadow plates closer to the Ringworld to
get the day/night cycle equal.
--
Regards
Stephen
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On 7-8-2018 8:22, Stephen wrote:
> On 06/08/2018 22:34, Mike Horvath wrote:
>> On 8/6/2018 5:15 PM, Mike Horvath wrote:
>>> An old scene, but I've been sprucing it up in preparation toward
>>> uploading it to the Object Collection. I can't remember if it's to
>>> proper scale however. Also I'm thinking there may be a little too
>>> much cloud cover.
>>>
>>>
>>> Mike
>>
>>
>> Also, due to the sun being an area light, the unlit regions are much
>> too small.
>>
>>
>
> I got similar results when I tried it. I suspect Larry Niven got his
> maths wrong. I had to move the shadow plates closer to the Ringworld to
> get the day/night cycle equal.
>
>
That, or scale down the area_light's effective surface. At this
planetary scale the area effect would be hardly noticeable imo.
--
Thomas
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On 07/08/2018 07:42, Thomas de Groot wrote:
> On 7-8-2018 8:22, Stephen wrote:
>> On 06/08/2018 22:34, Mike Horvath wrote:
>>> On 8/6/2018 5:15 PM, Mike Horvath wrote:
>>>> An old scene, but I've been sprucing it up in preparation toward
>>>> uploading it to the Object Collection. I can't remember if it's to
>>>> proper scale however. Also I'm thinking there may be a little too
>>>> much cloud cover.
>>>>
>>>>
>>>> Mike
>>>
>>>
>>> Also, due to the sun being an area light, the unlit regions are much
>>> too small.
>>>
>>>
>>
>> I got similar results when I tried it. I suspect Larry Niven got his
>> maths wrong. I had to move the shadow plates closer to the Ringworld
>> to get the day/night cycle equal.
>>
>>
He is not the only one who got his maths wrong. Of course I meant closer
to the star.
>
> That, or scale down the area_light's effective surface. At this
> planetary scale the area effect would be hardly noticeable imo.
>
A point light gives the same result.
--
Regards
Stephen
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On 7-8-2018 10:20, Stephen wrote:
> On 07/08/2018 07:42, Thomas de Groot wrote:
>> On 7-8-2018 8:22, Stephen wrote:
>>> On 06/08/2018 22:34, Mike Horvath wrote:
>>>> On 8/6/2018 5:15 PM, Mike Horvath wrote:
>>>>> An old scene, but I've been sprucing it up in preparation toward
>>>>> uploading it to the Object Collection. I can't remember if it's to
>>>>> proper scale however. Also I'm thinking there may be a little too
>>>>> much cloud cover.
>>>>>
>>>>>
>>>>> Mike
>>>>
>>>>
>>>> Also, due to the sun being an area light, the unlit regions are much
>>>> too small.
>>>>
>>>>
>>>
>>> I got similar results when I tried it. I suspect Larry Niven got his
>>> maths wrong. I had to move the shadow plates closer to the Ringworld
>>> to get the day/night cycle equal.
>>>
>>>
> He is not the only one who got his maths wrong. Of course I meant closer
> to the star.
>
>>
>> That, or scale down the area_light's effective surface. At this
>> planetary scale the area effect would be hardly noticeable imo.
>>
>
> A point light gives the same result.
>
Right. I would suggest then to test with a point light, following
Stephen's maths, then try some area_light until it fits.
--
Thomas
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On 07/08/2018 10:02, Thomas de Groot wrote:
> On 7-8-2018 10:20, Stephen wrote:
>> On 07/08/2018 07:42, Thomas de Groot wrote:
>>> On 7-8-2018 8:22, Stephen wrote:
>>>> On 06/08/2018 22:34, Mike Horvath wrote:
>>>>> On 8/6/2018 5:15 PM, Mike Horvath wrote:
>>>>>> An old scene, but I've been sprucing it up in preparation toward
>>>>>> uploading it to the Object Collection. I can't remember if it's to
>>>>>> proper scale however. Also I'm thinking there may be a little too
>>>>>> much cloud cover.
>>>>>>
>>>>>>
>>>>>> Mike
>>>>>
>>>>>
>>>>> Also, due to the sun being an area light, the unlit regions are
>>>>> much too small.
>>>>>
>>>>>
>>>>
>>>> I got similar results when I tried it. I suspect Larry Niven got his
>>>> maths wrong. I had to move the shadow plates closer to the Ringworld
>>>> to get the day/night cycle equal.
>>>>
>>>>
>> He is not the only one who got his maths wrong. Of course I meant
>> closer to the star.
>>
>>>
>>> That, or scale down the area_light's effective surface. At this
>>> planetary scale the area effect would be hardly noticeable imo.
>>>
>>
>> A point light gives the same result.
>>
>
> Right. I would suggest then to test with a point light, following
> Stephen's maths, then try some area_light until it fits.
>
No, don't follow my maths.
Using the data from this site. I did a quick model.
http://www.alcyone.com/max/reference/scifi/ringworld.html
I adjusted the Shadow square ring radius until the day/night cycle
looked equal.(multiplied the radius by 0.587587699)
--
Regards
Stephen
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Preview of image 'ring_3_0000.png'
![ring_3_0000.png](/povray.binaries.images/attachment/%3C5b69749c%40news.povray.org%3E/ring_3_0000.png?ttop=428607&toff=150&preview=1)
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On 07/08/2018 11:29, Stephen wrote:
> No, don't follow my maths.
>
> Using the data from this site. I did a quick model.
> http://www.alcyone.com/max/reference/scifi/ringworld.html
> I adjusted the Shadow square ring radius until the day/night cycle
> looked equal.(multiplied the radius by 0.587587699)
A close up of the terminator on the Ringworld.
The area light does make a difference.
Using
light_source { // Light_Source2
< 0.000000, 0.000000, 0.000000 >, colour rgb <1.000,1.000,1.000>*1.500
area_light <3.400000,0.000000,0.000000>,
<0.000000,3.400000,0.000000>, 23, 23
circular
orient
adaptive 5
--
Regards
Stephen
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Download 'ring_2bm2_0000.png' (9 KB)
Preview of image 'ring_2bm2_0000.png'
![ring_2bm2_0000.png](/povray.binaries.images/attachment/%3C5b697560%241%40news.povray.org%3E/ring_2bm2_0000.png?ttop=428607&toff=150&preview=1)
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Am 07.08.2018 um 12:33 schrieb Stephen:
> A close up of the terminator on the Ringworld.
> The area light does make a difference.
> Using
> light_source { // Light_Source2
> < 0.000000, 0.000000, 0.000000 >, colour rgb <1.000,1.000,1.000>*1.500
> area_light <3.400000,0.000000,0.000000>, <0.000000,3.400000,0.000000>,
> 23, 23
>
> circular
> orient
> adaptive 5
And it better does. You don't want the light to blink off
instantaneously - you do want some twilight time.
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On 7-8-2018 12:51, clipka wrote:
> Am 07.08.2018 um 12:33 schrieb Stephen:
>
>> A close up of the terminator on the Ringworld.
>> The area light does make a difference.
>> Using
>> light_source { // Light_Source2
>> < 0.000000, 0.000000, 0.000000 >, colour rgb <1.000,1.000,1.000>*1.500
>> area_light <3.400000,0.000000,0.000000>, <0.000000,3.400000,0.000000>,
>> 23, 23
>>
>> circular
>> orient
>> adaptive 5
>
> And it better does. You don't want the light to blink off
> instantaneously - you do want some twilight time.
>
I agree. What I meant earlier was that, with the camera at /planetary/
distances from the ring, the penumbra would hardly be visible. Up close,
and more so on the ring surface, of course the penumbra matters.
However, if the area_light is set while the camera is at a /planetary/
distance, it will most probably be grossly exaggerated because otherwise
you would not be able to see it properly in a render.
--
Thomas
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On 07/08/2018 11:51, clipka wrote:
> Am 07.08.2018 um 12:33 schrieb Stephen:
>
>> A close up of the terminator on the Ringworld.
>> The area light does make a difference.
>> Using
>> light_source { // Light_Source2
>> < 0.000000, 0.000000, 0.000000 >, colour rgb <1.000,1.000,1.000>*1.500
>> area_light <3.400000,0.000000,0.000000>, <0.000000,3.400000,0.000000>,
>> 23, 23
>>
>> circular
>> orient
>> adaptive 5
>
> And it better does. You don't want the light to blink off
> instantaneously - you do want some twilight time.
>
That is the whole idea, I believe. ;)
As for maths the area_light axis vectors should be doubled to 6.8 not 3.4
I was thinking radius as opposed to diameter.
--
Regards
Stephen
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