On 4/18/2024 1:35 PM, Alain Martel wrote:
> Le 2024-04-18 à 08:56, RATH, CHRISTOPHER A a écrit :
>> On 4/17/2024 12:17 PM, Cousin Ricky wrote:
>>> On 2024-04-17 08:28 (-4), RATH, CHRISTOPHER A wrote:
>>>>>
>>>> This is a ways from being done, but I wanted to share the updated image
>>>> with the bubbles fixed.  The balloon texture is still not quite right,
>>>> even when I render with radiosity (which this version does not).
>>>
>>> I doubt radiosity makes any difference here.  I would give Alain's
>>> suggestion of blurred reflection a try.  If you haven't seen it yet, the
>>> technique is at:
>>>
>>> https://wiki.povray.org/content/Knowledgebase:Language_Questions_and_Tips#Topic_13
>>>
>>> To avoid having this technique stall and take forever, use Alain's
>>> modification:
>>>
>>> https://news.povray.org/49b9809b%241%40news.povray.org
>>>
>>> And I would cut the reflection in half or even lower; and if you're
>>> using finish-level Fresnel, remember to use the reduced reflection as
>>> its argument:
>>>
>>> finish
>>> { fresnel 0.5
>>>    reflection { 0.5 fresnel }
>>>    conserve_energy
>>>    ...
>>> }
>>>
>>> The reflection of the water highlights on the right edge of the balloon
>>> looks suspiciously metallic.  Is this not a rubber balloon?
>>>
>> I looked at the code for doing the blurred reflections and started 
>> experimenting with it.  I was able to get a nice blurring mirror using 
>> CSG objects and this technique where I can play with the variables.
>>
>> However, the balloon is an isosurface with a pretty small accuracy 
>> value to remove artifacts, so hitting it with 40X more rays drops the 
>> rendering to a halt.  I can get it to go with a small blur count, but 
>> I don't think that will give me the blur effect.
>>
>> I'm still playing with it.  If I can find a good way to create the 
>> balloon using CSG instead of isosurfaces that may be the better 
>> solution, since I don't need a bumpy surface.
>>
>> -- Chris R
> Then, you need to use the micro-normal technique. Add a normal statement 
> scaled very small.
> 
> normal{granite scale 0.01}
> 
> Then use a reasonable amount of antialiasing. Without antialiasing, the 
> micro-normal will result in a grainy image.
> 
> Optionally : You may add some averaged blurring using a small number of 
> textures. Using averaged textures and micro-normals, you can use about 4 
> to 6 averaged textures and get very good results.
Here's what I've come up with so far.  I abandoned the texture-averaging 
blurring technique because it's just too slow, even using the ovus.  I'm 
using a micro-normal instead.  I also added a small transmit value along 
with the filter to the pigments.  The colors have also been muted to 
better reflect what happens when you inflate a balloon.  The reflection 
has been toned down quite a bit.

These are test renderings of the distant balloon cluster and the nearby 
balloon.  Getting them to look like this in the full scene is still a 
bit of a challenge.

-- 
-- Chris R

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