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On 4/27/2017 5:37 PM, Bald Eagle wrote:
> Stephen <mca### [at] aol com> 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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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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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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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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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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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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Stephen <mca### [at] aolcom> wrote:
> You do ask awkward questions. ;-)
It's a talent I've honed through decades of constant practice. ;)
> 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.
I was sort of thinking along the lines of "given the gears available" - how
would one calculate which gear combination to use that would most accurately
reflect a given orbital period. Likely just a novelty, so if Jupiter's 67th
moon is a day off once every year, then it's likely no one would know.
Hell, I didn't even know Jupiter had ***67 Moons*** until I took a look over at
http://www.windows2universe.org/our_solar_system/planets_table.html
:O
As for Scale, scale, scale .... yeah. I had been dabbling with doing a solar
eclipse scene, and it really drives home the concept of numbers being
"astronomical". I did a quick edit to do a sort of top-down view of the
planetary orbits, and --- there definitely needed to be some scaling UP of the
planet sizes and scaling DOWN of the orbital radii, just so that there was shot
in Hell of seeing a point of light on the screen where a planet ought to be.
It _really_ gets one thinking about how the heck they actually see things that
"small", THAT far away and even have some notion about what the rest of the
galaxy looks like....
I've also disambiguated rotation and revolution. :)
In my dabbling, I was wondering if the sun has a tilt to the plane of the solar
system, and
do any of the celestial objects have a secondary rotation - a wobble, if you
will, of their primary axis of rotation?
In POV-Ray terms, I guess that would be a rotate y, rotate z, and then a second
rotate y (looking top - down at the N pole).
.....and I'm back off to work.
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"Bald Eagle" <cre### [at] netscapenet> wrote:
> In my dabbling, I was wondering if the sun has a tilt to the plane of the solar
> system,
http://www.caltech.edu/news/curious-tilt-sun-traced-undiscovered-planet-52710
Huh. How 'bout that.
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"Bald Eagle" <cre### [at] netscapenet> wrote:
and
> do any of the celestial objects have a secondary rotation - a wobble, if you
> will, of their primary axis of rotation?
and
https://en.wikipedia.org/wiki/Axial_precession
Must
Learn
Something
Every
Day
"... However, due to the gradually increasing luminosity of the Sun, the oceans
of the Earth will have vaporized long before that time (about 2,100 million
years from now)."
Hmmmm....
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On 5/5/2017 7:54 PM, Bald Eagle wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> and
>> do any of the celestial objects have a secondary rotation - a wobble, if you
>> will, of their primary axis of rotation?
>
> and
>
> https://en.wikipedia.org/wiki/Axial_precession
>
>
> Must
> Learn
> Something
> Every
> Day
>
>
Yes, very interesting. When you stop learning you stop living.
Metaphorically speaking.
I've heard of Planet X and Planet 9 but I have not read how its
existence was deduced.
Thanks for that.
> "... However, due to the gradually increasing luminosity of the Sun, the oceans
> of the Earth will have vaporized long before that time (about 2,100 million
> years from now)."
>
> Hmmmm....
>
>
You weren't planning to be around for it, were you? :)
--
Regards
Stephen
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