Clouds and transparent (alpha blended) objects


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Hi,

Is there a solution to properly render transparent objects (alpha blending) and 3D volumetric clouds correctly, no matter the viewer position (Unigine 2.13)? We are currently using render_clouds_transparent_order as zero since most of the time you are at ground level and want to render all transparent objects on top of clouds, but sometimes we go up, above clouds or even have transparent big objects in distance that appear in front of clouds.

Kind Regards,
Adrian L.

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Hi Adrian,

We are working on a proper solution, but currently only discrete switch is available (render_clouds_transparent_order). So, when you are 100% sure that you are looking through the clouds you need to use 1, in other cases 0.

Thanks!

 

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  • 2 months later...

Hello Unigine Team,

are there any updates on this feature and when it is going to be available?

Do you plan to provide a depth and denisty texture of the clouds for custom shaders?

We have always the case that aircraft are above or below cloud level. Lights and particle systems are always visible at the moment.

Thanks.

 

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Hi Sebastian,

We are constantly working on clouds improvements. In 2.14 we plan to add lights support (such as Omni), so the clouds can be locally lit from inside.

Regarding the alpha blended objects (such as particles) - we have prototype that needs to finished (I'm afraid it would not be included in 2.14 due to big research underneath), so it would be available a bit later (2.15 is the optimistic version, but more likely 2.16+).

As an alternative temporary solution that may can solve couple of the issues we can modify engine so it would automatically group alpa-blended surfaces in groups (before-clouds -> inside-clouds -> clouds -> after-clouds). In that case alpha-blended objects inside clouds will not sort correctly anyway, but the overall look from the ground or from above the clouds would be better. If that's would be enough I think we can spend some time implementing this prior to 2.14 SDK update.

API access to the depth clouds texture would be available when the research would be finished. At this point of time you can get only the clouds screen texture (no depth).

Thanks!

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45 minutes ago, silent said:

As an alternative temporary solution that may can solve couple of the issues we can modify engine so it would automatically group alpa-blended surfaces in groups (before-clouds -> inside-clouds -> clouds -> after-clouds). In that case alpha-blended objects inside clouds will not sort correctly anyway, but the overall look from the ground or from above the clouds would be better. If that's would be enough I think we can spend some time implementing this prior to 2.14 SDK update.

So when two cloud layers are active render order would be kind of:  opaque -> alpha blendend above cloudlayer high -> cloudlayer high -> alphablended below cloud layer high and above cloud layer low -> cloud layer low -> alphablended below cloud layer low.

This would be a nice improvement.

We may play arround with the clouds screen texture at first.

Thanks.

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So when two cloud layers are active render order would be kind of:  opaque -> alpha blendend above cloudlayer high -> cloudlayer high -> alphablended below cloud layer high and above cloud layer low -> cloud layer low -> alphablended below cloud layer low.

I'm afraid, that's not possible currently to achieve. Clouds are rendered in a single pass, so we can't sort things additionally in between the separate cloud layers. So we can stick with the previous approach.

More sophisticated sorting and blending is planned for the future (due to complex research).

Thanks!

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Ok I understand, we would also be fine with a simple order: alpha blendend above lowest cloud layer base -> cloudlayers -> alphablended below lowest cloud layer base

Thanks

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Hello,

We too have this kind of requirements (being able to render alpha blended materials when on ground with clouds above, and clouds below with alpha blended mterials above).

In our own case, things may get a bit more complex as some objects are alpha blended *and* very near the camera (fast moving rotor), both when above, inside and below the clouds.

Thanks!

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