A transparent ceiling that does not transmit light? (3delight)

roezaka

I need to render the room from a high position of the camera, for this I remove the ceiling, but then the light passes through it and the lighting becomes not natural. Can this be fixed somehow?

Richard Haseltine

Create>New IIray Section Plane Node, position it so it is just below the ceiling, and in its Parameters turn on Clip Lights.

Paintbox

I believe there is a way using section planes : 

https://blog.irayrender.com/post/48117954581/section-planes

roezaka

https://imgur.com/mcEUW7a

With ceiling

https://imgur.com/TdbCz4t

Without

https://imgur.com/zOh36yO

https://imgur.com/UsTMkB4

  With section Plane

 

Where am I wrong?

Richard Haseltine

I'm a little confused now - I thought you wanted to render the scene from high up, but you are rendering it from in front - or is that just for illustration purposes? I can't really tell where the plane is, it would be better to upload the imges to your post then we could view them full size by clicking them.

roezaka

Richard Haseltine said:

 or is that just for illustration purposes?

This is for illustration.

 

Richard Haseltine

But the ceiling is still off - the Section Plane will hide (in the render) things that are visible, it won't do anything to things that are hidden. Show the ceiling, place the plane just under it, turn clip lights on, and render.

roezaka

Thanks! I understood how it works. But I was hoping that this would also work on 3delight. But no :( Is there a way to do something like this on 3delight?

Sven Dullah

roezaka said:

Thanks! I understood how it works. But I was hoping that this would also work on 3delight. But no :( Is there a way to do something like this on 3delight?

It's very simple;)

Select the ceiling in the scene tab and in the surface editor, apply the OmUberSurface shader, turn on Fantom. Now the ceiling will cast shadows but be invisible to the camera. Simple demonstration, a spotlight, a ground plane, a second plane (ceiling) just under the spotlight, with Fantom active:

Richard Haseltine

Not pre-set, it is possible to use Shader Mixer with a RayTest brick (I can't recall the exact name, last time I did this was in DS 3, or possibly even DS 2) to tell   eye rays (coming from the camera) from light or reflection rays and use that to set the opacity - that way you can make the surfaces transparent when looked through directly but opaque to lights and in reflections.