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From: Bald Eagle
Subject: re Cassini
Date: 27 Apr 2017 14:25:01
Message: <web.5901ff37711d262c437ac910@news.povray.org>
Just throwing this out there in case someone wanted to jump on a fun project /
resurrect an old one, before I did:

It would be fun to render / animate Saturn and its rings ---- with a Monolith in
full view   :D

Preferably by someone named Dave.
Because then we could all say, "Just what do you think you're doing, Dave?"
and
"That's a very nice rendering, Dave. I think you've improved a great deal. Can
you hold it a bit closer?"

;)


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From: Stephen
Subject: Re: re Cassini
Date: 27 Apr 2017 14:44:24
Message: <590203c8$1@news.povray.org>
On 4/27/2017 3:24 PM, Bald Eagle wrote:
> Just throwing this out there in case someone wanted to jump on a fun project /
> resurrect an old one, before I did:
>
> It would be fun to render / animate Saturn and its rings ---- with a Monolith in
> full view   :D
>
> Preferably by someone named Dave.
> Because then we could all say, "Just what do you think you're doing, Dave?"
> and
> "That's a very nice rendering, Dave. I think you've improved a great deal. Can
> you hold it a bit closer?"
>
> ;)
>
>
>

I'm on it.
I started a month ago working on an Earth - Moon orrery animation with 
Saturn in the background.
Nothing to show yet as I'm modelling it in Blender and haven't rendered 
it with PovRay yet.
One problem is that the image maps I have are uniform across the the X 
axis. So show no rotation on the planet or rings. :(

I'm having the usual problems you get with orreries. Scale and scale.

-- 

Regards
     Stephen


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From: Stephen
Subject: Re: re Cassini
Date: 27 Apr 2017 14:51:06
Message: <5902055a$1@news.povray.org>
On 4/27/2017 3:44 PM, Stephen wrote:
> Nothing to show yet as I'm modelling it in Blender and haven't rendered
> it with PovRay yet


But this gives an idea of the layout. As you can see there is still a 
bit to do. Animate the gears and get the clouds to display properly.

https://youtu.be/7yAYTllKCic

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: re Cassini
Date: 27 Apr 2017 16:40:01
Message: <web.59021e5b981bf41cc437ac910@news.povray.org>
Stephen <mca### [at] aolcom> wrote:

> I started a month ago working on an Earth - Moon orrery animation with
> Saturn in the background.

Oh my - that ought to be a fairly complex project  :O
I somehow haven't thought of tackling one of those yet - though my apple peeler
is closely related  ;)
It brings to mind the one in Pitch Black, and the truly awesome one in The Dark
Crystal.
and then there's _this_ guy:
http://zeamon.com/wordpress/?page_id=526

> Nothing to show yet as I'm modelling it in Blender and haven't rendered
> it with PovRay yet.
Ah Blender.   Lots of buttons.  :D

> One problem is that the image maps I have are uniform across the the X
> axis. So show no rotation on the planet or rings. :(

I had done a quick seach for povray saturn, and there may be some older Saturn
ring projects you might make good use of.

Good work - nice job on the gears  :)   Are they 'simple' gears or true
involutes?


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From: Stephen
Subject: Re: re Cassini
Date: 27 Apr 2017 17:33:12
Message: <59022b58@news.povray.org>
On 4/27/2017 5:37 PM, Bald Eagle wrote:
> Stephen <mca### [at] aolcom> wrote:
>
>> I started a month ago working on an Earth - Moon orrery animation with
>> Saturn in the background.
>
> Oh my - that ought to be a fairly complex project  :O

It is more of a Blender learning experience.

> I somehow haven't thought of tackling one of those yet - though my apple peeler
> is closely related  ;)

Actually not so much so. I've taken so long because when I made an 
accurate gear train. You could not see the detail when it was animated. 
So I cite Artistic licence and will pockle it. ;)

Hmm! an apple peeler. That sounds interesting. If you have a partially 
peeled apple that would be more difficult. I would say.
Images? :)

> It brings to mind the one in Pitch Black, and the truly awesome one in The Dark
> Crystal.

I wish I watched films, I feel out of touch. :)

> and then there's _this_ guy:
> http://zeamon.com/wordpress/?page_id=526
>

Yes, that is nice. I would not mind having one of those at home. :D


>> Nothing to show yet as I'm modelling it in Blender and haven't rendered
>> it with PovRay yet.
> Ah Blender.   Lots of buttons.  :D
>

And shortcuts. Thank goodness it is my fingers that do the remembering. :)

>> One problem is that the image maps I have are uniform across the the X
>> axis. So show no rotation on the planet or rings. :(
>
> I had done a quick seach for povray saturn, and there may be some older Saturn
> ring projects you might make good use of.
>

The image map I used for the rings was a cut down version of Bjorn 
Jonsson's from when PovRay only had a maximum of 256 entries. That 
limitation has been removed. So when I write the PovRay textures I'll 
have better textures. His planet textures have more detail.

> Good work - nice job on the gears  :)   Are they 'simple' gears or true
> involutes?
>

The planetary gears are true involutes but they are a lot of work so for 
speed the others are simple, for the moment.

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: re Cassini
Date: 27 Apr 2017 19:15:02
Message: <web.590242d7981bf41cc437ac910@news.povray.org>
Stephen <mca### [at] aolcom> wrote:

> Hmm! an apple peeler. That sounds interesting. If you have a partially
> peeled apple that would be more difficult. I would say.
> Images? :)

Indeed, but that would give me a good bit to think about   ;)

I will post the current state of the WIP over in pbi.

> > http://zeamon.com/wordpress/?page_id=526
> >
>
> Yes, that is nice. I would not mind having one of those at home. :D

I will have to cajole and shame my friend to make one with the laser cutter...

> The image map I used for the rings was a cut down version of Bjorn
> Jonsson's from when PovRay only had a maximum of 256 entries. That
> limitation has been removed. So when I write the PovRay textures I'll
> have better textures. His planet textures have more detail.

Yes, those were the ones I was thinking of.


> The planetary gears are true involutes but they are a lot of work so for
> speed the others are simple, for the moment.

They are a lot of work to get set up initially - it took me forever to get them
figured out, coded, and converted to SVG to test on the laser cutter.


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From: Stephen
Subject: Re: re Cassini
Date: 27 Apr 2017 20:30:48
Message: <590254f8$1@news.povray.org>
On 4/27/2017 8:13 PM, Bald Eagle wrote:
> Stephen <mca### [at] aolcom> wrote:
>
>> Hmm! an apple peeler. That sounds interesting. If you have a partially
>> peeled apple that would be more difficult. I would say.
>> Images? :)
>
> Indeed, but that would give me a good bit to think about   ;)
>
> I will post the current state of the WIP over in pbi.
>
>>> http://zeamon.com/wordpress/?page_id=526
>>>
>>
>> Yes, that is nice. I would not mind having one of those at home. :D
>
> I will have to cajole and shame my friend to make one with the laser cutter...
>

I would if I could. :)

>> The image map I used for the rings was a cut down version of Bjorn
>> Jonsson's from when PovRay only had a maximum of 256 entries. That
>> limitation has been removed. So when I write the PovRay textures I'll
>> have better textures. His planet textures have more detail.
>
> Yes, those were the ones I was thinking of.
>
>
It took me a while to find it again.

>> The planetary gears are true involutes but they are a lot of work so for
>> speed the others are simple, for the moment.
>
> They are a lot of work to get set up initially - it took me forever to get them
> figured out, coded, and converted to SVG to test on the laser cutter.
>
>

Have a look at this site. I know it's for Blender but there are 
calculators to help with the equations.
http://www.otvinta.com/index.html



-- 

Regards
     Stephen


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From: Cousin Ricky
Subject: Re: re Cassini
Date: 27 Apr 2017 21:01:28
Message: <59025c28$1@news.povray.org>
On 04/27/2017 10:24 AM, Bald Eagle wrote:
> Just throwing this out there in case someone wanted to jump on a fun project /
> resurrect an old one, before I did:
>
> It would be fun to render / animate Saturn and its rings ---- with a Monolith in
> full view   :D
>
> Preferably by someone named Dave.

Funny you should mention this.  I made a Saturn animation exactly 12 
years ago to the day.

I have posted it in p.b.a.


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From: Bald Eagle
Subject: Re: re Cassini
Date: 4 May 2017 17:25:07
Message: <web.590b63c5981bf41cc437ac910@news.povray.org>
Stephen,

What are you using to determine your gear tooth numbers?
Did you start from scratch, use existing plans, or some sort of gear train
calculator?

(I have piles and piles of plastic gears - I was wondering about finding the
best / approximately correct arrangement of the ones I have available.)


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From: Stephen
Subject: Re: re Cassini
Date: 4 May 2017 20:42:10
Message: <590b9222$1@news.povray.org>
On 5/4/2017 6:24 PM, Bald Eagle wrote:
> Stephen,
>
> What are you using to determine your gear tooth numbers?

You do ask awkward questions. ;-)

> Did you start from scratch, use existing plans, or some sort of gear train
> calculator?
>


Basically I use my fingers and integer arithmetic. Although a s/sheet 
helps. First you work out the final ratio which in that case was 28:1. 
28 revs of the earth in the same time that the Moon rotates once. (To 
keep the same face pointed towards the earth.) So it is number of teeth 
on the input gear to number of teeth on the output. But since I did not 
want to build all the bearings and supporting structure. I used a 
planetary gear chain. That uses specific ratios and diameters for the 
gears and I got them from this site: http://www.otvinta.com/index.html

After all that it was a wasted effort because it was indistinct and I 
might as well have use textures. So following the Animators guidelines I 
cheated and made sure that the gears meshed and no one would be able to 
tell it was not accurate. Smoke and mirrors. ;) The mind is easily fooled.

> (I have piles and piles of plastic gears - I was wondering about finding the
> best / approximately correct arrangement of the ones I have available.)
>
>
Best for what application? Remember when using compound gear chains the 
ratios are multiplied.
This is mostly from memory. I only did mechanical engineering at high 
school and that was a long time ago. So that is what I meant about doing 
it on my fingers. One step/gear at a time. ;-)
If I have not answered your question. Ask again.

-- 

Regards
     Stephen


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