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View Full Version : To Normalize or Not to Normalize



Schwyhart
05-22-2018, 08:19 AM
Any opinions on the matter?
Are there any gotcha's?

With normalize unchecked, the Light Intensity has to increase considerably to match.

If you don't know what this is, please visit: https://docs.lightwave3d.com/display/LW2018/Light+Normalize

Schwyhart
05-22-2018, 08:54 AM
141807
Normalize on
Linear light intensity 1.14lx
Render time 2 minutes 3 seconds

141806
Normalize off
Linear light intensity 20 lx
Render time 1 minutes 8 seconds

raymondtrace
05-22-2018, 09:10 AM
Well done. How did you come to 20 lux to match the first image? These two images are mostly indistinguishable when loaded as layers in Photoshop with the 'difference' blending mode.

mummyman
05-22-2018, 09:18 AM
Wow.. really big time hit. I'm assuming it'll be way bigger of a hit with more stuff in the frame. That's gonna drive me crazy on a project.

Schwyhart
05-22-2018, 09:28 AM
141808141809

These settings are the same on both images.

- - - Updated - - -


Well done. How did you come to 20 lux to match the first image?

It's not exactly the same. I just kept on increasing the value until the images looked similar.

Schwyhart
05-22-2018, 09:31 AM
Linear light samples are the same as well...10 samples. Ends is checked.

I increased the Interpolation Primary Rays to 256 after the images I posted here. Before it was 128.
Increasing it to 256 renders a smoother wall in the corners.

Schwyhart
05-22-2018, 09:37 AM
141811
This is what increasing the Primary Rays on Interpolation does. Increased render from 1m 8s to 1m 14s.
Normalize unchecked.

Schwyhart
05-22-2018, 10:20 AM
141813

Added the same settings as the toroid to the room.
Increased render time to 9m 51s. Makes sense because there are more reflections going on, but that's a big hit to render time.

Schwyhart
05-22-2018, 11:48 AM
All three objects with 10% roughness, 50% specular.

141814

Render time: 10m 30s
Linear light set to 20 lx
10 Samples
Normalize unchecked

Schwyhart
05-22-2018, 12:03 PM
All three objects with 10% roughness, 50% specular.

141815

Render time: 10m 37s
Linear light set to 1.14 lx
10 Samples
Normalize checked

Schwyhart
05-22-2018, 12:09 PM
In conclusion, it seems as though the scene will render faster with Normalize unchecked, even with the light intensity much higher.

Also, the render time increases dramatically when there is more than one object with Specular. To correct for this, you could lower the Reflection Recursion Limit's. For all of the above renders this was set to 4.
Lowering this value to 1 made the render time 8m 30s, but you lose a tiny bit of realism in the reflections.

Tim Parsons
05-22-2018, 01:10 PM
I think the Normalize button is there as a convenience to make it less PBR like - or at least that's how I take it. It's logical that a larger area light at the same lux level would output more light, but on more practical workflow issue normalizing the light makes some sense. These are interesting findings as to the render time differences and something that I had not discovered - thanks for sharing.

tburbage
05-23-2018, 09:17 AM
141807
Normalize on
Linear light intensity 1.14lx
Render time 2 minutes 3 seconds

141806
Normalize off
Linear light intensity 20 lx
Render time 1 minutes 8 seconds

I the thing I'm puzzled by with your numbers is why the Normalize ON scenario takes roughly 2x longer to render...

Schwyhart
05-23-2018, 11:41 AM
I tested again today and both rendered in 1m 11s
Here is the scene.

https://www.dropbox.com/s/w0zivx1i2erwjb0/NormalizeScene.zip?dl=0