Planetary Environment & Starfields - Examples Tweet

[linvanchene]

wallace posted an example orbx file in the OR4 RC1 thread featuring a setup planetary scene:


viewtopic.php?f=33&t=68491&start=30#p343929

Default scene:

Default scene

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Some examples of adjusting parameters to yield different effects:

- Use the Sun Direction to change the position of the sun

Latitude -52

Latitude -71

Latitude -90

- Change Post Processing settings to affect the look of the sun

Post Processing Bloom

Post Processing no glare

- Ground Albedo is visible during day

Ground Albedo

- Ground emission is visible during night

Ground emission

Ground emission off

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In the above images the Panoramic camera with Projection Spherical (equirectangular) is used.

Examples with the thin lens camera:

Thin lens camera

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- Adjust the Power of the Star field map

Star field - custom map

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[linvanchene]

Questions:
1) Is it possible to move the camera back several 1000's of km to see the whole planet without distorting the view? (solved)

Use the "Altitude" settings in the planetary environment and adjust the "Up-vector" in the camera settings

2) Is there a way to add an additional layer for a cloud map to keep clouds separate from the Albedo ground map?

3) Can we somehow increase the atmosphere height and give it a different color for artistic effect?

[frankmci]

Questions:

1) Is it possible to move the camera back several 1000's of km to see the whole planet without distorting the view?

2) Is there a way to add an additional layer for a cloud map to keep clouds separate from the Albedo ground map?

3) Can we somehow increase the atmosphere height and give it a different color for artistic effect?

I can't give you any reply to 2) and 3), other than that I hope they add those features, as they'd be super handy for the company where I work and the kind of work we do. But as for 1) I think you just need to add a new thin lens camera and render from that.

[linvanchene]

updated several times to provide more accurate information

I think you just need to add a new thin lens camera and render from that.

Thank you for pointing me in the right direction.
But I still have not figured out the proper settings completly.

I can randomly move around the mouse in the viewport until the planet is fully visible from the provided scene.
But then the starfield is somewhat distorted.

I can achieve some interesting effects but do not understand what is happening.

My mindset is from another application (e-on vue) and I have not yet figured out the "logic" how to control the camera position in relation to the planetary surface in Octane.

I have not figured out which settings to use to move the thin lens camera away from the earth.



example:
In vue the origin x/y/z (0/0/0) is a place on ground level of the planet.
- You move the camera up 4'000 km (z = 4'000'000 if unit 1m)
- Then you rotate the camera down to face the earth

Side note:
It would probably be challenging to perform this action without having some kind of additional perspective viewport in which you can control the camera by rotating it with gizmo controls.

An additional challenge of actually finding the proper distance settings for the camera is caused by the very large scale.

If the planetary system has an earth like radius and atmosphere you can know in which height to set the camera.
- 400 km for shots from an orbiting space station
- 4'000 - 10'000 km to get a shot of the whole planet from further in space.

In Octane standalone I use the left mouse button to tilt the camera down to see the object from bird perspective.
Then I use the mouse wheel to zoom out.

However what confuses me is that not only the y (height) is being adjusted but the x and z values as well.

I still do not understand which thin lense camera position settings to enter to have a camera located at 10'000 km (=10'000'000 m) in orbit looking down on the planet.



Is there some kind of local / world / planetary dimension toggle I am overlooking?

[frankmci]

linvanchene, I'm feeling my way in the dark with this Planetary Environment node, just like you, so I could be completely wrong about this. With that said, here are my thoughts/interpretations, having played around with it a bit.

This is a shader that renders the inside of an infinite sphere to look AS IF the center of that sphere was on or near a planetary surface. There is no real planetary geometry, there is no real camera position. It's not like you could build a solar system with multiple planets and make a Planetary Environment for each one and expect them to all render correctly at the same time. In other words, it's a fast, clever fake. That's fine, and very useful in certain situations, but it's not a universal atmosphere shader.

The camera used to shade the inside of that sphere is a spherical projection camera that's part of the node structure. That spherical camera's "orientation", for the purpose of how it renders the surface, is driven the XYZ Position, XYZ Target and Up Vector attributes. Its position relative to the lat and long of "planet surface" is controlled by the Planetary Angle attribute and its distance from the "planetary surface" is controlled by the Altitude. You can then add a "real" camera in 3D space to view portions of the inside surface of that infinite sphere. So what you see in your final render is actually a combination of setting used to generate the surface and the world-space positioning of the thin lens camera used to view it.

No, it is not at all intuitive. But that's because we want this to behave like two distinct objects, a camera and a finite, spherical planet, that both share a 3D coordinate system, when really it is something else, altogether. Really, it's the inside of an infinite sphere whose surface is produced by a clever shader, and a camera that occupies a position and orientation within the 3D space enclosed by the infinite sphere.

I hope that makes some sense, and I hope I'm not horribly off in my interpretation of what's going on.

- Frank

[linvanchene]

updated with more screenshots

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Frank, thank you so much.

The camera used to shade the inside of that sphere is a spherical projection camera that's part of the node structure. That spherical camera's "orientation", for the purpose of how it renders the surface, is driven the XYZ Position, XYZ Target and Up Vector attributes. Its position relative to the lat and long of "planet surface" is controlled by the Planetary Angle attribute and its distance from the "planetary surface" is controlled by the Altitude. You can then add a "real" camera in 3D space to view portions of the inside surface of that infinite sphere. So what you see in your final render is actually a combination of setting used to generate the surface and the world-space positioning of the thin lens camera used to view it.

This made me realize what setting I was overlooking!

To better understand the scale I created a simple scene with two spheres and a ground plane.

sample scene - two spheres with ground plane

I attached the .obj in a .zip file:

plane sphere 2x v1001.zip

zip file with .obj of one plane with two spheres

(62.32 KiB) Downloaded 273 times

With the help of the two spheres as reference point for me it was easier to understand what changing the planetary environment settings does.
Hiding the ground plane yields a more artistic effect but then it is once again more difficult to understand that the planet is actually "below" or "behind" the ground plane.

Planetary environment behind ground plane

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The Altitude is another crucial setting:

Altitude 2900000

Altitude 9900000

Altitude 38920000

In any case it seems you can create some moons with sphere primitives and combine them with the planetary environment.

planetary environment combined with spheres

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There is no real planetary geometry, there is no real camera position. It's not like you could build a solar system with multiple planets and make a Planetary Environment for each one and expect them to all render correctly at the same time. In other words, it's a fast, clever fake. That's fine, and very useful in certain situations […]

Agreed, I also do not expect that the "Planetary environment" provides every single one of those complex options a dedicated landscape simulation software offers.

So far I find the Octane "Planetary environment" interesting because it provides results very quickly.

Ground elevation with random image

Still, for those interested a tutorial by Soberdreamer that gives some ideas how planetary scenes are created in e-on vue:

http://orig09.deviantart.net/0660/f/201 ... 4nz8jz.pdf

[…]but it's not a universal atmosphere shader.

I realize now that the "planetary environment" effect is calculated for the displayed "background".
However, it would be interesting if we could just apply a " planetary shader" to any sphere primitive we place in the scene.

Example - A sun system environment:

The sun and starfield settings would remain as they are.
The ground and atmosphere of the original "planetary environment" could be disabled.
A simplified sun system with some planets and moons is created by placing sphere primitives in the scene and applying the "planetary shader".

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You can then add a "real" camera in 3D space to view portions of the inside surface of that infinite sphere.

I still wonder if there is a way not to have the planetary environment centered at the middle or the bottom middle of the viewport?

example - sphere not centered

For some shots it would be interesting to have the planetary environment in just one corner of the image.

Basically what seems missing (or is not possible based on what Frank described) is a way to "offset" the planetary environment from its origin point.

Or is there another simple setting I am overlooking?

[frankmci]

I think your experiments with the additional spheres explain what I mean better than what I was trying to do with words. Yes, exactly, the planet will always be behind/below every other "real" object, because the planet is not really an object at all, it's part of the shader created environment.

For some shots it would be interesting to have the planetary environment in just one corner of the image.
Basically what seems missing (or is not possible based on what Frank described) is a way to "offset" the planetary environment from its origin point.
Or is there another simple setting I am overlooking?

From what I've seen, you can shift the planet surface off the image vertical center line using just the Environment node's camera, although it introduces other distortions.

The first image is a schematic of what's really going on, which is that the planet is actually part of the environmental projection map. The second image shows a render where the planet is offset from the center line using just the Environmental camera, and you can see that the Milky Way is badly twisted when it should be straight. If you use a second camera, as in the second image, you can offset the planet from the centerline without adding noticeable distortion.

With the right combination of Environmental camera Altitude and the second render camera's orientation and FOV, you should be able to frame the planet pretty much any way you want.

Edit: I'm not certain you can't get the same offset without distorted results with just the Environmental Node's own camera (pardon the double negative), but it seems a lot easier using a second camera. I don't think this environment node is really designed for what we are trying to make it to do (distant space shots, as opposed to high altitude or low orbit), but it's interesting to push it.

[linvanchene]

Thank you once again.

It turned out I was trying to just use the mouse controls to navigate the viewport and did not actually adjust the Up-vector of the camera in the menu.

Up-vector x / y / z = 1 / 0.652 / 0

Up-vector & postprocessing

Starfield Projection

I still have difficulties to predict the results when I use projection modes.
A Thin lens camera in combination with Box Projection mode sometimes helps to counter distortions when using images that were not intended for spherical use.

starfield projection mode box

I don't think this environment node is really designed for what we are trying to make it to do (distant space shots, as opposed to high altitude or low orbit), but it's interesting to push it.

The Panoramic camera seems really intended for a very specific use.

But yes, it can be fun to push the limits a bit to find out what kind of random effects you can create when you are using features in ways they were not intended for...

[linvanchene]

The goal of this example is to have the starfield as "background" image fit the screen exactly.

A special thank you for roeland who had released a camera mapping script here:

viewtopic.php?f=73&t=37574&p=344873#p165233

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While setting up the planetary environment you may have to change the "Up-vector" of the camera.
This means any texture applied as starfield will now probably also look in another direction.
With the help of the camera mapping script by roeland it is possible to match the image settings to the camera.

Before applying script

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When the script is applied the image orientation now matches the camera:

script applied

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All that is left is to adjust the UV transform Scale parameters so the starfield image matches the viewport:

script applied - transform scale adjusted

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[gurel]

Does anyone have an approach to this within the C4D plugin as opposed to Octane Standalone?

I'm trying to achieve a view of a planet but can't seem to hit the mark.

One work around is to group the scene and camera into a null object and then rotate that so the planet comes into view but it isn't preferable as it throws the scene navigation into disarray.

Thanks,

Gurel