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Visibility

Table Of Contents


Introduction

The per-object visibility options in Redshift allow you to control if and how objects participate during the various stages of rendering.

By default, the 'Casts Caustic Photons' option is Off. To render with caustics, you will need to turn this option on for any object that will cast caustic effects in your scene.


Accessing The Options



Visibility Options

Ray Visibility

Rays shot from the camera are called primary rays. Rays that are shot from the surface of an object for reflection, refraction or global illumination are called secondary rays.

The following examples show the effect of changing the 'Primary Ray Visible' and 'Secondary Ray Visible' options on the sphere.


Primary Ray Visible On, Secondary Ray Visible On

Primary Ray Visible Off, Secondary Ray Visible On. The sphere cannot be seen from the camera, but is visible in shadows, reflection, refraction and GI.

Primary Ray Visible On, Secondary Ray Visible Off. The sphere is invisible for all effects except camera rays and shadows. Notice the lack of GI on the sphere.


Shadows


Sphere has 'Casts Shadows' enabled.

'Casts Shadows' is disabled. Notice the missing shadow under the sphere.


Elephant has 'Self Shadows' enabled.

'Self Shadows' is disabled. Notice the missing shadows on the elephant.


Sphere has 'Casts AO' enabled

'Casts AO' is disabled. Notice the missing ambient occlusion under the sphere.


Refraction


Sphere with 'Visible in Refractions' Off

Glass plane with 'Casts Refractions' Off


Reflection


Sphere with 'Visible in Reflections' Off

Mirror with 'Casts Reflections' Off


Global Illumination


Examples using Irradiance Cache


'Receives GI' Off. The sphere receives no GI, but light is still bouncing off it and can be blocked by it.

'Visible to Non-Photon GI' Off. The sphere is receiving GI, but is not casting any GI shadows. Notice how there is extra brightness beneath the sphere.


Examples using Photon Mapping


The plane near the right wall has 'Casts GI Photons' On and 'Visible to GI Photons' On. The photons bounce off the plane and hit the right wall.

'Casts GI Photons' Off and 'Visible to GI Photons' On. Photons do not bounce off the plane (the right wall is darker), but are still blocked by it.

'Visible to Photon GI' Off on the sphere. Irrespective of the 'Casts GI Photons' setting, photons cannot find the sphere and so neither bounce off it or are stored on it. As far as photon mapping GI is concerned, the sphere does not exist.


Examples using Caustics


Cylinders have 'Casts Caustic Photons' On and 'Visible to Caustic Photons' On. Notice the caustic patterns on the ground geometry.

'Casts Caustic Photons' Off, 'Visible to Caustic Photons' On. No caustic photons are generated.

'Casts Caustic Photons' On, 'Visible to Caustic Photons' Off. Caustic photon rays go through the cylinders. As far as caustics are concerned, the cylinders do not exist.