Vray Notes General


For dark scenes – we use gamma compensation under Vray colour mapping tab. Use Dont affect colours with a gamma of 2.1 for better sampling in the darks.

for vray cg cars – http://jeffpatton.net/
for fluid simulations and volumetrics
for best post motion blur – Reel smart motion blur

Types of lights and their uses:
1) Area – the best light ever.. behaves how a normal set bounce lights. they have most natural shadows.. they are expensive but less than point/sphere/dome lights.
2) sphere lights (point lights) – only use when necessary.. the slowest light of all.
3) Dome lights – second best Light .. mostly useful when doing outdoors. Works best when teamed up with an HDRI.
4) IES Lights (phillips lights have IES) – most accurate lights based on light manufacturing profiles

Ray Depth – how many time a ray gets subdivided into more secondary/tertiary rays when it hits a point. Subdiv controls the number of secondary rays it will shoot. There are subdiv controls on almost every object in Vray.. the trick is to be smart and use higher subdiv on selected object rather than using a global multiplier under the vray settings

When using dome lights.. the sun shadows never come out proper.. so either we remove the sun from the HDRI itself or clamp it.. and use a directional light to cast sharp sunny shadows.

Shadow bias is good for removing shadow artifacts .. larger values help in achieving this.
However if u have a very close-up geometry decresing shadow bias leads to more accurate details (would generally work with procedural textures).

on dome light – dome texture is where you would plug in your hdri map

Tex adaptive (might be doing importance sampling)??

VFB – Vray frame buffer
Use VFB History for storing render images (‘H’ button)

Invisible option under each light hides the primary visibility of the light

3s bit full float with piz compression

for post motion blur in nuke – render vectors and use motion blur

Image Samplers:
Fixed – Simple, straight forward – will subdivide samples evenly across the image
Adaptive DMC – better and faster for stuff with small details (with fur, DOF, MB)
Adaptive subdivision – better and faster for non geometry heavy details. regular scenes

For max subdivisions you can go very high without sacrificing render time as it will only do it where its needed. But if you do increase min samples it will slow down the render. Check values for min samples are not often above 4.

Grainy noise – adjust image sampler samples
Blotchy Noise – adjust Indirect Illumination samples


1) Irradiance (maybe interusable as FG?)

Min rate/Max rate – Are resolution multipliers controlling the final sampling of GI .. 0 is full res and negative values are square rooting..
subdivs – 100 for final renders

Camera Type – Spherical for rendering 360 env maps

Irradiance Engine – Pathtracing?
Photon Engine – Photon Emission


Photon emission – needed for caustics

light cache under secondary bounces – bake final gather

MODE – This is where you do the baking for GI

difference between animation modes and multiframes mode?

Path tracing
Importance sampling – samples based on an image map and uses more samples from brighter parts
Spherical Harmonics?

Colour Mapping – for correct linear workflow
Alembic – open source object data format


Andrew Silke

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