Karma

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renderer

LOP

SHIFT + R = » switch to karma

Outputs

  • MPlay - can set up to send to MPlay
  • Driver - Progressive / Buckets (with progresisve passes +1 ) fastest way tofrist pixel

Rerender fragment

  • Data Windows NDC

Workflow to optimize

  1. turn off indirect and get direct light clean (if note it will continue spreading wrong resoults)
  2. Sometimes render x2 resolution but 1/2 samples > deniose > scale down get sharpen edges and more details with same times. (especially for motion). Works only because of noise consistency Karma is producing.
  3. sequences

Karma render settings

Karma Render Properties - Can add multiple Render settings.

Karma sampling

Pixel samples

Main quality driver. Pixel Samples Multiplayer. Values: 32 - acceptable / 128 - clean
Render Times: Predictable - doubles when param doubles. and have linear relation with render size

Indirect rays

How much samples shot from shading point. Convergence mode: (how total ray samples are calculated) (montecarlo convergence)

  • Variance - Default Min / Max - treshold ! advanced tab > noise level is drivng min and max. lower noise level will shoot more max 0.005 very clean.
    • Min -
    • Max - 9 / 12 / 30 - Small increase in render times. But pixel sample is doing more cleaning.
  • Distributed - Manual - Ability to change on types - so in specific situations when scene have one type of rays
  • Path Traced - progressive like in viewport (not final) - longer with lot of bounce lights. (can help with far a way ropes)

Noise levels

Fine detail levels. check if its noise or not enough samples

  • 0.02 noisy / 0.01 default / 0.005 max / below its not super cleaner (not shooting more rays) Render times can increas much

Oracle

Variance pixel samples, based on noise level at selected rendre pass (ie. beauty pass) during rendering Will ignore darker values more. If noise is everywhere oracle will go to max pix samples (Amount ovf variance that trigers more rays ) Pixel sample thershold Im wię◙kszy tym wiekszy musi byc noise zeby odpalił dodatkowe raye

  • varaince like in min/max

Turn of by setting to uniform

Limits

How many bounces allowed. Can save a lot of render time Bounces GI - 3 is enough for sky (is slow and more change not so much) / for sunlight will change
Color limit - will darken when to low

Russian Roulette - Killing some samples in every next bounce. Value is number of bounce when to start reducing. Its good to use cause after 2 bounce rays ale much less important. At 0 will kick of quickly and produce noise.

Light quality

Global multiplayer. Specific setups in light actors directly. Sampling mode

  • Light Tree beneficial when lot of lights. gnerally good
  • Uniform - single light

1- minimum to work but its ok. No need to increase in simple scenarios

Volumes

Dicing

Effect on pieces we don’t see that is reflected or use indirect ilu. Multiply - for reflection and refraction & displacement. Default ok.

Indirect Guide

Can optimize indirect bounces Will initialize with pre pass

  • not big quality difference. - expensive not always change q.

Denoise

Workflow with denoiser: - increase resolution, decreas pixel samples
can soften small details ,

Denoise in COP

Need 2 additional passes, Albedo, N .

  1. File (load render passes)
  2. Denoise AI
    How low samples can use with denoise
  3. Scale down

Image output > filters > Denoiser OCIO (open color) Add 1

  • Output space ‘ACES - ACEScg’
  • Input Space: data

Lights

Interior render with area lights in windows

  • dome light especially with texture is harder to calculate
  • spot light
  • aera lights- not better than doom but direct tan be little bit cleaner.
  • portal lights - to focus render but same quality in karma not huge effect
not all lights work with xpu
xpu dont use exposure. (change in intensity )

IES

can download from pixar renderman site

Shading

When light hit surface it can be:

  • reflection
  • absorption
  • transmission

Shaders

  • USD Preview surface - need uv nodes and dont have subsurface. Basic one ! poor only for usd
  • MaterialX - for Karma XPU -
  • Pyro - shaders are ok
  • Karma Pyro preview - karma pyro for XPU
  • Lens Shader - inside camera use lens shade (must be mat context not material lib ) - can add distortion and aberration

Features

  • Diffuse
  • Albedo
  • Base Color Albedo multip: - sth with absorbtion
  • Specular
  • any point of surface
    • dielectric: 2-8%
    • semi-conductor 8-40$
    • metal - 40 +
  • Fresnel
    • at any angle (Is spec refl !)
  • Roughness
  • Absorption
    • we see colors throughh absorption (color are absorbed by heat) BLACK BODY IS NOT ONLY A PERFECT ABSORBER BUT ALSO A PERFECT emitter of heat. Hence the black container will cool down faster. Dark-colored materials absorb visible light better than light-colored materials. That’s why the dark side of the card heats up first.
  • IOR
  • Anisotropic
    • directional refl
  • Sheen - subtle dif rough
  • Coat - double highlights
  • Transparency
    • ray limitatins - up refl and refr limits if black resoults to low limits
  • Sub Surf - single scattering - like a marble. will soften a shadows random walk -new one
  • Tansparency
  • Transmition @ distance (at what distance will be fully trans. color ) : how its color wwhen going throu medium

-0–

lambertian reflection

All diffuse is technicaly subsurface but not visible water based body liki skin have deeper

Camera

DOF

under view: - focal len and horizontal aparture .
Dof - Shift + F - show plane / Shift + Click LMB - to show when to shift
F- stop - how much blur

Blur

Motion Blur

On movement

  1. need to Cache
  2. in camera shatter open, shatter closed

Velocity Blur

relay on attribute

  • v - geometry
  • vel - vdb grid / vector grids

AOV (Render Vars)

  • passes
  • beauty - default
  • C plane - is beauty pass
LPE Tags

Divide light s to componenets for evey light
Compose in COP

  • delete channel
  • rename channels
  • screen mode if rendered with taged layers.
Cryptomats

render vars

Deep camera maps.

heavy - volume information’s. can compo with semi

https://matlib.gpuopen.com/main/materials/all