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On 09/08/2018 00:37, Mike Horvath wrote:
> On 8/8/2018 5:35 PM, Stephen wrote:
>> On 08/08/2018 22:02, Mike Horvath wrote:
>>> On 8/8/2018 1:05 PM, Stephen wrote:
>>>> On 08/08/2018 15:08, Mike Horvath wrote:
>>>>> Okay, I uploaded my scene to here:
>>>>>
>>>>>
http://lib.povray.org/searchcollection/index2.php?objectName=Ringworld&version=2.0&contributorTag=SharkD
>>>>>
>>>>>
>>>>> I also attached my latest render to this post. The shadow squares'
>>>>> widths now match what was apparently stated in the books. The
>>>>> shadowed regions on the ring look much better now.
>>>>>
>>>>> However, I had to double the height of the shadow squares in order
>>>>> to block out the sun. See the parameter
>>>>> `RWorld_Shadow_Square_Width`. I'm not sure why this was necessary,
>>>>> as the original height was equal to the sun's diameter, and should
>>>>> have fully blocked its light.
>>>>>
>>>>
>>>> Do the two area_light vectors <Axis_1> and <Axis_2> extend beyond
>>>> the star's volume?
>>>>
>>>
>>> 1. the axis lengths are equal to the sun's diameter
>
> Oops! I screwed up here. See my other post. They're fixed now.
>
>
>
>>> 2. the area light is circular and oriented
>>> 3. the sun's diameter should be equal to the shadow squares' height
>>> according to Niven's website
>>
>> Just a check list.
>> I just noticed that the data I was looking at was from the game. Oops.
>>
>
> Here's a scan from the game:
>
> https://img.fireden.net/tg/image/1464/06/1464060167901.jpg
>
> The shadow squares seem much smaller than they should be.
>
>
It looks deliberate to give unequal day night cycles.
I can't remember what the book said.
>
>>
>>> 4. an array of point lights in the shape of a sphere does not suffer
>>> from the issues I'm experiencing
>>>
>>
>> How do you do that without them clustering at the poles?
>>
>>
>
> I don't. They do cluster! I should investigate a "good enough" sphere
> packing formula.
From my reading. There is no general solution for placing equidistant
points on a sphere. :(
I have managed to extract the coords of a Blender Icosphere which is
made up of equilateral triangles. 42 points, a bit on the high side for
lights. If it is any use here they are.
BTW Blender used Z up coords.
<0.000000, 0.000000, -1.000000>,
<0.723607, -0.525725, -0.447220>,
<-0.276388, -0.850649, -0.447220>,
<-0.894426, 0.000000, -0.447216>,
<-0.276388, 0.850649, -0.447220>,
<0.723607, 0.525725, -0.447220>,
<0.276388, -0.850649, 0.447220>,
<-0.723607, -0.525725, 0.447220>,
<-0.723607, 0.525725, 0.447220>,
<0.276388, 0.850649, 0.447220>,
<0.894426, 0.000000, 0.447216>,
<0.000000, 0.000000, 1.000000>,
<-0.162456, -0.499995, -0.850654>,
<0.425323, -0.309011, -0.850654>,
<0.262869, -0.809012, -0.525738>,
<0.850648, 0.000000, -0.525736>,
<0.425323, 0.309011, -0.850654>,
<-0.525730, 0.000000, -0.850652>,
<-0.688189, -0.499997, -0.525736>,
<-0.162456, 0.499995, -0.850654>,
<-0.688189, 0.499997, -0.525736>,
<0.262869, 0.809012, -0.525738>,
<0.951058, -0.309013, 0.000000>,
<0.951058, 0.309013, 0.000000>,
<0.000000, -1.000000, 0.000000>,
<0.587786, -0.809017, 0.000000>,
<-0.951058, -0.309013, 0.000000>,
<-0.587786, -0.809017, 0.000000>,
<-0.587786, 0.809017, 0.000000>,
<-0.951058, 0.309013, 0.000000>,
<0.587786, 0.809017, 0.000000>,
<0.000000, 1.000000, 0.000000>,
<0.688189, -0.499997, 0.525736>,
<-0.262869, -0.809012, 0.525738>,
<-0.850648, 0.000000, 0.525736>,
<-0.262869, 0.809012, 0.525738>,
<0.688189, 0.499997, 0.525736>,
<0.162456, -0.499995, 0.850654>,
<0.525730, 0.000000, 0.850652>,
<-0.425323, -0.309011, 0.850654>,
<-0.425323, 0.309011, 0.850654>,
<0.162456, 0.499995, 0.850654>
--
Regards
Stephen
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