Add notes about Ray Portal BSDF quirks #104807

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Brecht Van Lommel merged 3 commits from Alaska/blender-manual:portal-notes into main 2024-06-04 17:06:07 +02:00
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@ -14,14 +14,15 @@ It acts much like a :doc:`Transparent BSDF </render/shader_nodes/shader/transpar
render passes are passed through,
and it is affected by light path max transparent bounces.
.. note::
- The portal only allows rays to pass through in one direction.
- The Ray Portal BSDF only allows rays to pass through it in one direction. Add a
second portal at the target location to make rays go in the other direction as well.
Alaska marked this conversation as resolved Outdated

I would add:

Add a second portal at the target location to make rays go in the other direction as well.

I would add: > Add a second portal at the target location to make rays go in the other direction as well.
- Light sampling does not work efficiently through portals. This can lead to increased
Alaska marked this conversation as resolved Outdated

I suggest:

Light sampling does not work efficiently through portals. This can lead to increased noised from lights on the other side of portals. Particularly small lights may be very noisy, or not pass through at all.

I suggest: > Light sampling does not work efficiently through portals. This can lead to increased noised from lights on the other side of portals. Particularly small lights may be very noisy, or not pass through at all.
noised from lights on the other side of portals. Particularly small lights may be very
noisy, or not pass through at all.
- Some of the techniques Cycles uses to reduce noise does not work through portals.
This leads to issues like increased noise from lights passing through portals,
or if the light is small, it's light may not pass through the portal.
Inputs
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