Author Topic: Eclipse at real scale?  (Read 415 times)

Offline bigben

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Eclipse at real scale?
« on: August 23, 2017, 07:31:12 AM »
Is it possible to set up an eclipse at real scale?  I've tried an object and a planet but neither block the sun. Background increased to include the "moon"
« Last Edit: August 23, 2017, 07:51:09 AM by bigben »

Offline Dune

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Re: Eclipse at real scale?
« Reply #1 on: August 23, 2017, 09:36:36 AM »
I did some testing too, but couldn't solve it. Strange, even when receive shadows of surfaces is checked in atmo (which should block the sun's haze, AFAIK). Perhaps you need to fake it with a glowing ring object? And main sun not illuminating atmo, maybe a lesser sun that does.

EDIT: no that wouldn't work, obviously.
« Last Edit: August 23, 2017, 09:50:22 AM by Dune »
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Offline icarus51

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Re: Eclipse at real scale?
« Reply #2 on: August 28, 2017, 06:48:00 AM »
Hi all,

So is it impossible to render an eclipse at real scale? I tried some situations but i got the same results, no eclipse at all.
It is as if the planet, or the object, was shielded by the atmosphere of the planet Earth, in the rendering. If the planet is near the sun, aside, is visible but when the object screens the sun become transparent. I would like to know the reason for this issue by an expert or a Terragen programmer. 
Where is the error, if is an error?
Thanks.

Offline Kadri

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Re: Eclipse at real scale?
« Reply #3 on: August 29, 2017, 12:41:05 AM »

Looks like the sun(and the other lights too) is more like a point and Terragen puts the glow,visible disk etc. like kind of a postwork in the atmosphere. It is most evident when you render in space. There is no sun visible without "visible disc" checked. 

I couldn't get a basic eclipse too with a standard way.
It worked only with cheating by using a luminous sphere behind the moon and disabling "glow in atmosphere and clouds" in the Sunlight node.
A corona is possible too with an atmosphere and-or clouds on that sphere of course as you know.

The scene is pretty basic but might be useful for others maybe.


Offline icarus51

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Re: Eclipse at real scale?
« Reply #4 on: August 29, 2017, 08:11:03 AM »
Right.

I don't know because Terragen has this behaviour. Aside for the landscape, you should be able to represent the solar system, the space, the space phenomena and so on, to have a good realism. Instead you have to resort to tricks to get these things.

I wonder: But in movies that use Terragen how do they make these situations?

The only eclipses I've gotten are actually within the Earth's atmosphere with a 'fake' moon (distance not real, moon not real in size).
I will try again but i'am not optimistic. In case i'll let you know.

I repeat: I would like someone to explain to me whether it is possible to make a true eclipse (with all the real data at real scale) or if instead we have to resign ourselves to make mere falsifications. Beautiful but unrealistic. :(



Offline jaf

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Re: Eclipse at real scale?
« Reply #5 on: August 29, 2017, 09:33:08 AM »
Tough one.  I tried using three suns.
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Offline Kadri

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Re: Eclipse at real scale?
« Reply #6 on: August 29, 2017, 03:05:38 PM »
Right.

I don't know because Terragen has this behaviour. Aside for the landscape, you should be able to represent the solar system, the space, the space phenomena and so on, to have a good realism. Instead you have to resort to tricks to get these things.

I wonder: But in movies that use Terragen how do they make these situations?

The only eclipses I've gotten are actually within the Earth's atmosphere with a 'fake' moon (distance not real, moon not real in size).
I will try again but i'am not optimistic. In case i'll let you know.

I repeat: I would like someone to explain to me whether it is possible to make a true eclipse (with all the real data at real scale) or if instead we have to resign ourselves to make mere falsifications. Beautiful but unrealistic. :(

Terragen isn't a scientific accurate real world simulator in the way you think.
In movies they cheat everything.
Threads like this are kind of curious and fun exercises or an important thing for work too, if the software can or can't do this or that mostly.
There is not one software at all that renders everything realisticly in one go.

Bigben knows these things. It would be nice to have more then the software can deliver in any given state of course.
« Last Edit: August 30, 2017, 07:15:52 AM by Kadri »

Offline Dune

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Re: Eclipse at real scale?
« Reply #7 on: August 30, 2017, 06:54:51 AM »
You're close, Jaf.
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Offline icarus51

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Re: Eclipse at real scale?
« Reply #8 on: August 30, 2017, 08:04:26 AM »
Quote
Terragen isn't a scientific accurate real world simulator in the way you think.
In movies they cheat everything.
Threads like this are kind of curious and fun exercises or an important thing for work too, if the software can or can't do this or that mostly.
There is not one software at all that renders everything realisticly in one go.

Bigben knows these things. It would be nice to have more then the software can deliver in any given state of course.

If the situation is this then i can only cheat to render my eclipses. Like i show with these pics that i rendered by TG4.
Sun is by default, the moon is fake at high atmo altitude. The rock is for make shadow in the partial eclipse.

Cheers.

Note: Perhaps the big trick is to make a Fake sun, if possible, eclipsed by a Fake moon.


Offline fleetwood

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Re: Eclipse at real scale?
« Reply #9 on: August 30, 2017, 02:48:10 PM »
I used a planet sized "sun" (radius 6.268e+006) and a moon (radius 5.92e+006) planet object for this corona render. The apparent "sun" however is a luminous planet object with huge clouds.
The actual sunlight is there behind everything else and lighting up the cloud structures. The luminosity mostly just creates the small localized ring of light. 

It seems you can make the sunlight behave like a sphere like by increasing the visible disc angular diameter.
Here is an example where the sunlight was made a visible disc and given an angular diameter of 20 and it encroaches into the asteroid as if it were a sphere.
« Last Edit: August 30, 2017, 03:06:21 PM by fleetwood »

Offline bobbystahr

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Re: Eclipse at real scale?
« Reply #10 on: August 30, 2017, 05:53:47 PM »
nice work out...building TG muscles
something borrowed,
something Blue.
Ring out the Old.
Bring in the New

bobbystahr