© Bertrand Benoit

Table of Contents

This page provides details on the Lens Effects tools available in V-Ray for Unreal.



Overview


V-Ray Lens Effects simulates real-world camera lens effects such as bloom and glare. The plug-in uses a fast multi-threaded technique to compute the result and provide immediate update in V-Ray VFB. V-Ray Lens Effects are applied in the effectsResult channel together with other post effects executed over the RGB rendered image.

The Lens Effects fly-out is accessible from the Open lens effects settings button located in the V-Ray VFB Toolbar.

Additionally, V-Ray includes a standalone Lens Effects Generator Tool for composing custom lens filters.

The V-Ray Lens Effects window can be docked or undocked from V-Ray VFB by right-clicking the Open lens effects settings button.



UI Path



 ||V-Ray Frame Buffer Toolbar|| > Open lens effects settings button



Result Channel


 When V-Ray Lens Effects are used, a new channel called effectsResult will be created in V-Ray VFB. The RGB Channel button allows users to easily toggle between the effectsResult and original RGB channel.


 

Bloom/Glare Parameters


Save – Save the current Bloom and Glare settings as a preset which can be loaded later.

Load – Loads a pre-saved Bloom and Glare preset.

Reset – Resets the Bloom and Glare settings to their default values.

Bloom/Glare effect Enables the V-Ray Lens Effects.

Size – Specifies the size of the filter as percentage of the image's diagonal. See the Size example below.

Bloom – Controls the blend between bloom and glare. A value of 1 forces bloom to be applied to full extent and without any glare. A value of 0 removes the bloom completely and applies only glare. Values in-between blend the two effects proportionally. See the Bloom/Glare example below.

Intensity – Multiplier for the bloom/glare source bright pixels. Increasing the value can boost the effect by simulating up to 20 times brighter source. Values lower than 1 can be used to produce subtle bloom/glare from overbright sources. See the Intensity example below.

Threshold – Sets a minimum value for the rendered pixels to be considered as lens effects source. The Bloom/Glare effect will be generated only regarding pixels with larger value than the specified threshold.

Effect rotation – Rotates the final result effect, regardless of this is a filter image or a procedurally created one. 

Mode – Determines if the Bloom/Glare effect will be applied to the final image (in the effectsResult channel), stored into a separate render element, or both.

Cold/Warm – When enabled, the Bloom/Glare effect will be toned to cold hues. When disabled, the effects will receive warm hue. The hue shift requires Saturation values larger than 0. See the Cold/Warm & Saturation examples below.

Saturation – When the value is set 0, the effects use the original hue of the bright pixels to create bloom and glare. Larger values intensify the hue set with the Cold/Warm option. See the Cold/Warm & Saturation examples below.

Hardware Accelerated – Enable to calculate lens effects on the GPU. When multiple devices are present, V-Ray will prioritize the best one available.

Interactive – When enabled, the bloom/glare effect will be automatically recalculated and applied after any V-Ray lens effects parameter change.

Update effects – Manually forces the recalculation of the bloom/glare effects.

You can modify the frequency at which the lens effects are updated during progressive rendering via the Post effect rate parameter located in V-Ray Settings > V-Ray Render Elements. Choose between the presets if you want to see the lens effects updated more often during IPR.





Example: Size


Size = 1
Intensity (constant) = 1.00

Size = 10
Intensity (constant) = 1.00

Size = 20
Intensity (constant) = 1.00

Size = 30
Intensity (constant) = 1.00

Size = 40
Intensity (constant) = 1.00

Size = 50
Intensity (constant) = 1.00

Size = 60
Intensity (constant) = 1.00

Size = 70
Intensity (constant) = 1.00

Size = 80
Intensity (constant) = 1.00

Size = 90
Intensity (constant) = 1.00

Size = 100
Intensity (constant) = 1.00

1
100




Example: Bloom / Glare



Bloom = 0.0
Streak blur (constant) = 0.20

Bloom = 0.1
Streak blur (constant) = 0.20

Bloom = 0.2
Streak blur (constant) = 0.20

Bloom = 0.3
Streak blur (constant) = 0.20


Bloom = 0.4
Streak blur (constant) = 0.20


Bloom = 0.5
Streak blur (constant) = 0.20


Bloom = 0.6
Streak blur (constant) = 0.20


Bloom = 0.7
Streak blur (constant) = 0.20


Bloom = 0.8
Streak blur (constant) = 0.20


Bloom = 0.9
Streak blur (constant) = 0.20


Bloom = 1.0
Streak blur (constant) = 0.20

0.0
1.0





Example: Intensity



Intensity = 0
Size (constant) = 50

Intensity = 1
Size (constant) = 50

Intensity = 2
Size (constant) = 50

Intensity = 3
Size (constant) = 50


Intensity = 4
Size (constant) = 50


Intensity = 5
Size (constant) = 50


Intensity = 6
Size (constant) = 50


Intensity = 7
Size (constant) = 50


Intensity = 8
Size (constant) = 50


Intensity = 9
Size (constant) = 50


Intensity = 10
Size (constant) = 50

0
10





Example: Cold/Warm & Saturation


Saturation = 1.5
Cold/Warm On
Lights shaded with pure white color

Saturation = 1.0
Cold/Warm On
Lights shaded with pure white color

Saturation = 0.5
Cold/Warm On
Lights shaded with pure white color

Saturation = 0.0
Cold/Warm On
Lights shaded with pure white color

Saturation = 0.5
Cold/Warm Off
Lights shaded with pure white color

Saturation = 1.0
Cold/Warm Off
Lights shaded with pure white color

Saturation = 1.5
Cold/Warm Off
Lights shaded with pure white color

1.5
1.5



Aperture Shape


 Clicking the  button displays a short menu that resets all the parameters for a lens effect to their default values.

Blades – Enables the Blades effect.

Sides – Sets custom camera aperture blades number to be considered for the lens effects. This parameter directly controls the number of "rays" of the glare.

Rotation  Controls the rotation of the camera aperture and blades.

Streak blur – Determines the width of the angle at which glare rays spread. The larger the value, the wider the spread. If set to 0, rays are directional; if set to 1, glare rays spread out and completely blend together. Observe in the Streak blur example below how values in-between change the glare rays appearance.

Peripheral grating – Enables grating along the sides of the aperture shape. 

Density – Controls the density of the grating effect in percent, where 100 is fully black.

Length – Controls the length of the grate lines.

Zoom – Controls the size of the halo around the lights.

Slope – Controls the direction of the lines.

Strength – Controls the strength of the blades effects.

Occlusion – When enabled it controls the aperture shape by occluding part of it.

Symmetric – Enables symmetric occlusion of the shape. When disabled, the occlusion appears only on one side of the shape.

Percent – Controls how much of the shape is occluded.

Rotation – Determines the position of the occlusion over the shape by rotation.

Arc – Controls the arc of the occlusion. A value of 0 sets a straight line, while a value of 100 makes an arc.






Example: Streak blur




Streak blur = 0.0
Bloom (constant) = 0

Streak blur = 0.1
Bloom (constant) = 0

Streak blur = 0.2
Bloom (constant) = 0

Streak blur = 0.3
Bloom (constant) = 0


Streak blur = 0.4
Bloom (constant) = 0


Streak blur = 0.5
Bloom (constant) = 0


Streak blur = 0.6
Bloom (constant) = 0


Streak blur = 0.7
Bloom (constant) = 0


Streak blur = 0.8
Bloom (constant) = 0


Streak blur = 0.9
Bloom (constant) = 0


Streak blur = 1.0
Bloom (constant) = 0

0.0
1.0


Lens Scratches


Lens scratches – Enables the lens scratches effect.

Pattern – Specifies Random, Stripes, Square or Hexagonal type of pattern for the scratches: 

Symmetric – When enabled creates symmetric pattern of the scratches. This option is available only when Pattern is Random.

Streaks – Specifies the number of streaks that are clustered together. If Symmetric is enabled, the streaks are stemming from one point with equal angles. If Symmetric is disabled, the streaks are scattered from random angles.

Density – Controls the density of the scratches effect in percent, where 100 is fully black.

Length – Controls the length of the scratches.

Seed – Specifies a seed parameter to introduce variance in the randomization.

Slope variance – Randomizes the direction of the scratches.

Width variance – Randomizes the width of the scratches.

Zoom – Controls the size of the pattern.

Rotation – Determines the position of the scratches by rotation.

Strength – Controls the strength of the effect.



Lens Dust


Lens dust – Enables the lens dust effect.

Pattern – Specifies the Random, Square or Hexagonal type of pattern for the dust.

Density – Controls the density of the dust effect in percent, where 100 is fully black.

Radius variance – Specifies a variance in the radii of the dust dots. A value of 0 makes the dust dots uniform.

Jitter – Controls randomization of the position of the dots.

Zoom –  Controls the size of the dust dots.

Rotation – Determines the position of the dust dots by rotation.

Strength – Controls the strength of the effect.



Obstacle Image



Obstacle image – When enabled an obstacle image can be specified. You can use it to simulate various effects on the camera lens. See how this changes the lens effects in the Obstacle Image example below.

Load Obstacle Image – Loads an obstacle image.

Zoom – Controls the size of the obstacle image. 

Rotation – Rotates the obstacle image. 

Strength – Controls the strength of the effect.





Example: Obstacle Images




Obstacle images used












Size (constant) = 50
Bloom (constant) = 0.5


Filter Image


 Enabling this rollout disables the controls for the generated filter:

Filter image – Enables a filter image from the Filter generator tool to be used.

Load Filter – Specifies the path to a filter kernel. You can create filters using the Filter generator tool which comes with the V-Ray for Unreal installation.



Aperture Preview


 The Aperture Preview panel is loaded by default, but can be minimized like the other Aperture groups. The aperture shape shows the result of the applied lens effects.



File Names of Saved Channels


As expected, channels will keep their names as displayed in the VFB when saving them to a single .vrimg or .exr file (using the V-Ray raw image file option from the Frame buffer rollout or the Save all image channels to single file VFB button). The same channel names will be appended to the files when you use the VFB button Save all image channels to separate files.

However, using the Save separate render channels option from the Frame buffer rollout to save all layers as separate files will save the effectsResult channel to a file with the text RGB_color appended to its name, and the RGB channel as origRGB instead.