Power vs Intensity

[Leftover]

Is there difference in using Photon Power Multiplier or Intensity for lights/luminous surfaces?

[Janusz Biela]

Is there difference in using Photon Power Multiplier or Intensity for lights/luminous surfaces?

This is BIG DIFFERENCE!

Power is multiplay strong of light without bloom effect.
This is "exponential" for lights or "limitdr" for lights effect.
Power shader is KEY for good renders If You can use this and know how it works You can render very high quality scenes....

[Leftover]

What do you mean by "bloom"? "Overburned" areas?

[Janusz Biela]

What do you mean by "bloom"? "Overburned" areas?

Yes overbright near light sources.

[Leftover]

i see, thanks.
So Power multiplier allows to increase "indirect" (if this word can be used in such context) part of light while keeping "direct" part weak. That's very useful tip

[jure]

Is there difference in using Photon Power Multiplier or Intensity for lights/luminous surfaces?

Power controls the intensity of bounced light (photons) only! Direct light is not affected.
For example: imagine you have sun shining through a window. The sun makes a nice bright area on the floor but the room is very dark. When you increase intensity of sun the light on the floor will become too strong - overburned. This is where photon power comes to the rescue. Instead of increasing light intensity you add photon power to it. This way the light hitting the floor will not be overburned but the room will receive enough bounced light.

Hope this explains it.

[Janusz Biela]

Remeber: 10-15 Power is maximum (sometimes I saw in V-ray 150-200 from small lights)

[larry_g1s]

Great explanation guys...thanks.

[Janusz Biela]

For lamps inside room and fill lights (ceilin hide fill light) it is good: Power maximum 10, Area light Inverse Dist 2, beige colours (no red and yellow !!)
For fill Area Lights - outside behinde windows : Power maximum 10 , Area Lights Inverse dist 1, blue/gray colour
Minimum 20 bounce lights (for mix colours) and Power in Kray maximum 0.5 (1.0 default is too strong - make bad contrast)

Sun (beige colour - not yellow !!!) Powe Shader 3-8 Inverse Distance 1 (Inv. dist 2 for Sun is bad idea)