compositor doesnt mix unrendered render layers well
Closed, ResolvedPublic

Description

System Information
windows 10 x64 , nvidia geforce 970

Blender Version
Broken: 2.78.5
Worked: 2.78c

Short description of error
compositor doesn't mix un-rendered render layers well, in 2.78c if you mix a rendered layer to an un-rendered one it considers the un-rendered render layers as zero alpha, but now it consider it as full white.

Exact steps for others to reproduce the error
this is in 2.78c

this is in 2.785

Bastien Montagne (mont29) triaged this task as Normal priority.Jul 19 2017, 10:26 AM

Not squre what the issue is here, one way or the other unrendered layer is by definition invalid and more or less undetermined, random data… Changes in how we show here does not really matter imho? @Sergey Sharybin (sergey) should know better though.

even so, there is a certain behavior that has changed between the two versions, which means old files won't render the same way, and needs to incorporate new ways to work around them and without any new benefits!

now i need to render each empty layer to an empty alpha before mixing, and that can be troublesome with many layers and time consuming, or remix layers before each render shot which still time consuming.

Any news on the possibility getting the old behavior?

Now i have to render ALL render layers in the composite tree -which adds 1min for each empty renderlayer- to get the previous result, and 2.79 is needed because of the denoiser.

thanks, old behavior is BACK.