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Problem front layer keeping keeping transparent over backgroung

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Claude Rozsa
Problem front layer keeping keeping transparent over backgroung
on May 9, 2020 at 9:28:34 am

Good morning,
I hope everyone here has escaped the attack of Covid19 and is in good shape.

I have a problem while inserting my planet in the middle of the rings of Saturn.

I have tried in my project to respect certain characteristics of this planet.
Saturn's radius is 58230 kms
It's farther ring is 302000 kms wide and its external radius 483000 kms.
This explains in the final comp the relative smallness of the planet itself which is not to be seen in usual pictures of models. I've used a ratio of the different surfaces relative to the radius of the planet itself for my project.

When I installed the planet in the middle of the rings with an add mode one can see through the planet the rings behind and through the rings in front of it. I don't see where I made an error.
Here are screen captures of the different comps:

Final Comp:

Ring comp:

Planet comp:

I've used Element 3D for the rings with an ice texture as Saturn's rings are 95% ice.
I've used the alphabetical numbering of the rings as used by Nasa and scientists, they are position from the nearer to the farthest of the planet with those names and not in alphabetical order.
Of course there should be some reflectivity of the planet's color on them which I didn't realize yet and I must finalize also the lighting which is not satisfactory.
For the Planet and the Stars I've used VC-ORB by following Andrew Kramer excellent tutorial.
I'm using AE CC 2018. All my software are updated. I don't want to update to AE's latest one as this is a project I've been working on for a long time and don't want to take any compatibility risks.

Lastly I'm not a professional and don't pretend to become one, this is a hobby; I'm making a video of different ones I've shot during my 10 or so trips to Pompeii and Herculaneum since 1958.

Thanks in advance for your help to solve this problem.


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Graham Quince
Re: Problem front layer keeping keeping transparent over backgroung
on May 9, 2020 at 10:24:37 am

I hate to plug my own tutorial, but I think you can solve this problem using alpha mattes and expressions.

In that tutorial, I'm only using a 2D solid for the rings, but I use Orb's hemisphere with an expression option to flip the shape between up and down.

Re-reading your post - I just spotted you're using Element for the Rings. Why not add the planet the same way? Create a sphere in Element for Saturn and add a texture.

And come to think of it, you could also check out Andrew Kramer's tutorial on World Position matte: - Free FX for amateur films - FX blog

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Claude Rozsa
Re: Problem front layer keeping keeping transparent over backgroung
on May 9, 2020 at 12:11:32 pm

Hi Graham,
Thanks for your suggestions; actually I have watched some of your tutorials and the Saturn one in particular.

Yes I have used VC-Orb for the planet. I just try to have my work organised and eventually be able to re-use a previous work that's why I have separated in 4 comps, the final work, the planet, the ring and the stars. I use Orb for the planet and the stars.

My problem here is that I don't understand why the back of the rings are visible through the planet and the lower part of the planet is visible through the front of the first ring. Is it because under AE we're not really in 3D but in 2.5?

Some guy shows in a long post how he succeeds to create a Z dimension in AE; If I remember well in a project using Particular and Form. But he doesn't give full explanation of how he does it, it's a truncated tutorial spoken at the speed of light!lol! I'm not too bad with English but there I'm immediately lost and also Particular is not obvious for an amateur like myself.

There is a very short clip on YouTube showing the result I want to achieve with the iced asteroids rings around Saturn, the guy who did it announced a tutorial and never did it. It's a pity.

I'll recheck Andrew's tutorial you're mentioning, I might even have downloaded for an eventual use.


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Graham Quince
Re: Problem front layer keeping keeping transparent over backgroung
on May 9, 2020 at 12:31:56 pm

To explain a little about how AE's 3D space works, you can have different layers interacting with each other in 3D space - but these layers are all 2D though they are able to have a z-depth position - hence 2.5D.

3D effects like Element, Orb, CC Particle World can all interact with AE's camera in 3D space, but each effect is still being applied to a 2D layer. So while they respond to 3D positioning, they are in their own 3D space. To get your Element rings to intersect your Orb planet, you need to "fake" that interaction.

Element has it's own 3D space, so adding Saturn into that effect (as another group) would let Element sort the intersection out for you. The alternative is to use World Position Matte with duplicates of Element, one above the Orb layer for the front particles, and one below Orb for the back particles.

If you were to use Cinema4D, every thing would be in one, true 3D space - but even using C4D Lite, it would still be a 3D effect on a 2D layer. - Free FX for amateur films - FX blog

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