I have a planetary atmosphere with both scattering and absorption 
interior media. It renders very slowly. Any tips on speeding it up? Thanks.


Mike

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On 2/5/2021 5:59 AM, Mike Horvath wrote:
> I have a planetary atmosphere with both scattering and absorption 
> interior media. It renders very slowly. Any tips on speeding it up? Thanks.
> 
> 
> Mike


Here is the media:


// atmosphere
#declare RWorld_Atmos_Color_Scatter	= <0.1, 0.3, 1.0>;
#declare RWorld_Atmos_Color_Absorb	= <0.9, 0.7, 0.0>;		// should be the 
inverse of RWorld_Atmos_Color_Scatter
#declare RWorld_Atmosphere_Object = difference
{
	cylinder {<0,+RWorld_Ring_Width/2,0>,		<0,-RWorld_Ring_Width/2,0>,	 
RWorld_Ring_Radius - 1}	//
	cylinder {<0,+RWorld_Ring_Width/2 + 1,0>,	<0,-RWorld_Ring_Width/2 - 
1,0>,	RWorld_Ring_Radius - RWorld_Atmosphere_Height}
	bounded_by
	{
		cylinder {<0,+RWorld_Ring_Width/2,0>,		<0,-RWorld_Ring_Width/2,0>,	 
RWorld_Ring_Radius - 1}
	}
	hollow
	material
	{
		texture
		{
			pigment {rgbt 1}
		}
		interior
		{
			media
			{
				scattering
				{
					4, RWorld_Atmos_Color_Scatter
				}
				density
				{
					// Reverse: It starts at 1.0 at the origin and decreases to a 
minimum value of 0.0 as it approaches a distance of 1 unit from the Y axis.
					function {1-f_cylindrical(x,y,z)}
					density_map
					{
						[0 rgb 0/10]
						[1-RWorld_Atmosphere_Height/RWorld_Ring_Radius rgb 0/10]
						[1 rgb 1/10]
					}
					scale RWorld_Ring_Radius
				}
			}
			media
			{
				absorption RWorld_Atmos_Color_Absorb
				density
				{
					function {1-f_cylindrical(x,y,z)}
					density_map
					{
						[0 rgb 0/10]
						[1-RWorld_Atmosphere_Height/RWorld_Ring_Radius rgb 0/10]
						[1 rgb 1/10]
					}
					scale RWorld_Ring_Radius
				}
			}
		}
	}
}

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Mike Horvath <mik### [at] gmailcom> wrote:
> I have a planetary atmosphere with both scattering and absorption
> interior media. It renders very slowly. Any tips on speeding it up? Thanks.
>
>
> Mike

it's likely not your media - but your media settings.

try:

http://news.povray.org/povray.newusers/message/%3C59a9ec1c%40news.povray.org%3E/#%3C59a9ec1c%40news.povray.org%3E

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hi,

Mike Horvath <mik### [at] gmailcom> wrote:
> On 2/5/2021 5:59 AM, Mike Horvath wrote:
> > I have a planetary atmosphere with both scattering and absorption
> > interior media. It renders very slowly. Any tips on speeding it up? Thanks.
>
> Here is the media: ...

tweaking the code may gain you some, but, perhaps, you can cheat and clip the
sphere/planet just behind the horizon, saving ~40%.


>       [0 rgb 0/10]

confused why you don't write just '[0 rgb 0]'.


regards, jr.

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Op 05/02/2021 om 11:59 schreef Mike Horvath:
> On 2/5/2021 5:59 AM, Mike Horvath wrote:
>> I have a planetary atmosphere with both scattering and absorption 
>> interior media. It renders very slowly. Any tips on speeding it up? 
>> Thanks.
>>
>>
>> Mike
> 
> 
> Here is the media:
> 

I am studying/testing your media, but need a little time...

-- 
Thomas

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On 2/5/2021 6:56 AM, Bald Eagle wrote:
> it's likely not your media - but your media settings.
> 
> try:
> 
>
http://news.povray.org/povray.newusers/message/%3C59a9ec1c%40news.povray.org%3E/#%3C59a9ec1c%40news.povray.org%3E
> 
> 

I'm not sure how that applies to my case. I am not using emissive media 
or the "samples" keyword.


Mike

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On 2/5/2021 9:52 AM, jr wrote:
> hi,
> 
> Mike Horvath <mik### [at] gmailcom> wrote:
>> On 2/5/2021 5:59 AM, Mike Horvath wrote:
>>> I have a planetary atmosphere with both scattering and absorption
>>> interior media. It renders very slowly. Any tips on speeding it up? Thanks.
>>
>> Here is the media: ...
> 
> tweaking the code may gain you some, but, perhaps, you can cheat and clip the
> sphere/planet just behind the horizon, saving ~40%.
> 
> 

It's actually a cylinder or ring, so it reflects upon itself on the insides.


>>        [0 rgb 0/10]
> 
> confused why you don't write just '[0 rgb 0]'.
> 
> 
> regards, jr.
> 
> 

I use fractions a lot and like to keep the source code tidy.


Mike

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Op 07/02/2021 om 04:41 schreef Mike Horvath:
> On 2/5/2021 6:56 AM, Bald Eagle wrote:
>> it's likely not your media - but your media settings.
>>
>> try:
>>
>>
http://news.povray.org/povray.newusers/message/%3C59a9ec1c%40news.povray.org%3E/#%3C59a9ec1c%40news.povray.org%3E

>>
>>
>>
> 
> I'm not sure how that applies to my case. I am not using emissive media 
> or the "samples" keyword.
> 

There is nothing really wrong with your code as far as I can tell and 
from own experience. From the outside (of the media) it is even rather 
fast due to the default intervals 1 and samples 1 (Yes! you /do/ use 
samples, even if you don't).

However, depending on the location of the camera within or without the 
media, render times can be very different; you even may need to increase 
the samples value to avoid splotches, and that will decrease render time 
even more although not that much.

Using media is time consuming. There is no alternative.

-- 
Thomas

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Le 2021-02-07 à 02:23, Thomas de Groot a écrit :
> Op 07/02/2021 om 04:41 schreef Mike Horvath:
>> On 2/5/2021 6:56 AM, Bald Eagle wrote:
>>> it's likely not your media - but your media settings.
>>>
>>> try:
>>>
>>>
http://news.povray.org/povray.newusers/message/%3C59a9ec1c%40news.povray.org%3E/#%3C59a9ec1c%40news.povray.org%3E

>>>
>>>
>>>
>>
>> I'm not sure how that applies to my case. I am not using emissive 
>> media or the "samples" keyword.
>>
> 
> There is nothing really wrong with your code as far as I can tell and 
> from own experience. From the outside (of the media) it is even rather 
> fast due to the default intervals 1 and samples 1 (Yes! you /do/ use 
> samples, even if you don't).
> 
> However, depending on the location of the camera within or without the 
> media, render times can be very different; you even may need to increase 
> the samples value to avoid splotches, and that will decrease render time 
> even more although not that much.
> 
> Using media is time consuming. There is no alternative.
> 

The default for samples is 10.
samples default to 1 when using sampling method 1 or 2.
The default are, as of version 3.6 :

sampling_method 3
intervals 1 //DO NOT increase !
samples 10

Increasing intervals dramatically increase the rendering time without 
giving any appreciable improvement.

samples 10 intervals 3 render slower than samples 50 intervals 1.

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Op 08/02/2021 om 16:16 schreef Alain Martel:
> Le 2021-02-07 à 02:23, Thomas de Groot a écrit :
>> Op 07/02/2021 om 04:41 schreef Mike Horvath:
>>> On 2/5/2021 6:56 AM, Bald Eagle wrote:
>>>> it's likely not your media - but your media settings.
>>>>
>>>> try:
>>>>
>>>>
http://news.povray.org/povray.newusers/message/%3C59a9ec1c%40news.povray.org%3E/#%3C59a9ec1c%40news.povray.org%3E

>>>>
>>>>
>>>>
>>>
>>> I'm not sure how that applies to my case. I am not using emissive 
>>> media or the "samples" keyword.
>>>
>>
>> There is nothing really wrong with your code as far as I can tell and 
>> from own experience. From the outside (of the media) it is even rather 
>> fast due to the default intervals 1 and samples 1 (Yes! you /do/ use 
>> samples, even if you don't).
>>
>> However, depending on the location of the camera within or without the 
>> media, render times can be very different; you even may need to 
>> increase the samples value to avoid splotches, and that will decrease 
>> render time even more although not that much.
>>
>> Using media is time consuming. There is no alternative.
>>
> 
> The default for samples is 10.
> samples default to 1 when using sampling method 1 or 2.
> The default are, as of version 3.6 :
> 
> sampling_method 3
> intervals 1 //DO NOT increase !
> samples 10
> 
> Increasing intervals dramatically increase the rendering time without 
> giving any appreciable improvement.
> 
> samples 10 intervals 3 render slower than samples 50 intervals 1.

I don't know where in the wiki there was a line saying defaults being 
intervals 1 and samples 1,1. Of course, I cannot find that paragraph 
anymore (typical!); but you are right of course: default samples is 10.

-- 
Thomas

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