Corona sun gobos please

[Evan Lindsay]

It would be wonderful to have a custom Corona gobos sun parameter or maybe modifier. Would be a HUGE improvement versus using subpar planes with opacity. I could see a vast variety of looks for this (similar to Greyscalegorilla).

My static pans need this, lol.

[aler]

+1
as an example:

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[Evan Lindsay]

My bad, I meant to post this in the 3ds Max group but should be global. Cheers.

[Beanzvision]

Hi, it's fine to leave it here ;)

[romullus]

Maybe i don't understand something, but how you imagine the gobos could work with the sun? I mean, contrary to regular light, Corona sun does not have size, so how would you determine the size of the gobo effect?

[Beanzvision]

Currently, the best option is to use standard C4D lights for the gobo effect. This will not work with IR but you can use Cinema's interactive render region if you're after a preview.

[davetwo]

This is my number one wanted feature in Corona. It would be really useful.

I dont have release 10 yeat as I need to work with a renderfarm... but I seem to remember that adding a texture to a corona light is now possible? Could you add at texture and just increase the directionality to get a similar result?

[Juraj]

Could you add at texture and just increase the directionality to get a similar result?

Yes. Sun is very much just directional spotlight :- ).

I would like to caution people about the result of this technique though. There are two types of dappled lights commonly used in photography:

1) Gobo Lights: A tiny spotlight in box with Gobo mask. The light needs to be strongly directional (small and powerful) as the distance between light source and Gobo Mask is relatively small. A Gobo mask added to CoronaLight or CoronaSun would need to feature virtual "distance" parameter.
2) Dappled light from Sun resulting from occluding objects like Curtain or Trees. And here is the main difference... these shadows exist because sun is at great distance from occluding object.

How varried and soft/strong dappled shadows look depends completely on that distance between occlusion (Tree) and light-source (Sun). Because the distance varries (Trees are 3D-dimensional) you get that beautiful variation, on/off look, etc.

If CoronaSun somehow integrated Gobo-Mask similar to Spotlight, it would never produce this result anyway. It would simply produce the exact result a Spotlight with Gobo-Mask does.
And I used a lot of trick to boost that technique, like using motion-blurred Gobo Masks. It's not the same.

Creating Opacity-Mapped planes is not inferior technique. It will always be necessary to achieve the simulation of what happens in reality. Light is always defined by space.

Here is funny WIP from my current project. In order to get what I want, there is exact and complicated 3D setup of Curtains, Trees, Cannopies and Occlusion Boxes outside of what camera sees. Single light source with flate gobo mask, virtually mapped at some distance would not give you this.

[Juraj]

Maybe i don't understand something, but how you imagine the gobos could work with the sun? I mean, contrary to regular light, Corona sun does not have size, so how would you determine the size of the gobo effect?

It would simply be virtual mapped plane (at virtual distance specified by parameter). Effectively like Maya Camera Plane mapping but just for Light.
Softness would obviously change by both this virtual distance, and the size of Sun. I mean Corona does have fake Sun size parameter to simulate softness that would otherwise only exist by Cloud occlusion :- ) This would be just another fake.

But there was already a request to do this for CoronaLight and that would be much better general solution since CoronaLight can create Sun just simply changing directionality. And it already has Texture mapping, but that happens at source (distance=0), so it doesn't simulate Gobo Effect correctly.
There are lot of additions the CoronaLight could get, and both Gobo and Barn Doors would be great choices.

[davetwo]

Since you can now add textures to lights in Corona 10 we're getting closer.... But the real trouble is that the strongly increasing the directionallity in corona lights (which is absolutely necessary) causes the need for many, many more samples and it makes renders un-usably slow.

Using redshift for example, you just focus the light and it has no noticable speed hit or firefly problems.

I think the name of this thread is misleading - we're not talking about using the actual Corona Sun. We're talking about making fake sunlight effects on walls where there isnt a full room build or we're already lighting with an hdri and just need some extra 'interest' in particular spot.

[artdude12]

+1 for Gobo Lights