Blend Weight do not work anymore in Post Processing Volumes. UE 4.11.2

Development Programming & Scripting Blueprint
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Post Processing Volumes.

Blend Weight and Blendables Array are no longer working correctly in 11.2 and cannot be adjusted from say .1 minimal blend to 1 full blend in the individually added blend array components used in Post Processing Volumes.

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Hi Nikolay,

Can you provide your material setup for this blendable. In the examples I have from 4.10 - 4.12 I see the same results.

I see several JIRA’s entered regarding Blend Weights, so it may be possible on of these has already been reported, but just want to confirm first.

Also, can you try your blendable on 4.12 Preview 5 that is available in the Epic Games Launcher to verify this hasn’t already been fixed.

Thank you!

Tim

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. You are right. I don’t have any problems in 4.12 Preview 5.

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Thank you for letting me know. :slight_smile:

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May I ask for an update of this issue? As there is still no public bug tracker access, I hope we can at least ask for details on issues in the tracker. I would like to know if this issue is fixed and if so, in what git commit I will find the fix.

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@anonymous_user_4324b52e

As I originally responded I was seeing no difference in the blends when I checked for versions 4.10-4.12 Preview 5. Looking at the 4.10, 4.11, and final 4.12 in the content examples for the post process blend example (stand 1.15). I checked these again to make sure that there haven’t been any changes and I see no noticeable difference between these two blendables.

If you’re having a specific issue that is a difference in how the post process volumes worked from a previous version to 4.12 feel free to enter a separate ticket for this to be investigated. Make sure to include the necessary information to reproduce the issue or provide a sample project that reproduces the differences between a previous version and the latest release version.

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Well, the thing is: We can’t upgrade to 4.12, yet, so I need to find the exact git commit of this fix to manually merge it into our code base. I already spent a few hours trying to work my way through all the git commits of the last few months but couldn’t find any relevant changes. As I don’t know what classes are involved exactly, finding the fixing commit is nearly impossible. So I would really like to get some details about this issue and hopefully the exact git commit :slight_smile:

Edit: We are on 4.11.2 right now and will not update to 4.12 for at least a few months.

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Since I do not know which JIRA that was entered actually fixed the issue during the 4.12 preview releases or if a specific JIRA actually was entered I only have a best guess with UE-30565 being the one to likely fix your issue. I posted the info below but I don’t have the direct Git commit link. Sorry.

UE-30565 - fix CL-3023490 for merge to Main (4.12 release merge CL-2974680)

Keep in mind that I do not guarantee this is a fix for your issue and if it’s not this CL then I’m not exactly sure where the fix was made.

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Thank you! I will test these changes tomorrow and let you know if it worked. In any case: thank you for your time.

Edit: Thank you again, this commit did indeed fix the issue. I ignored the commit before because the message only talked about Blend Radius and Priority, but it seems those issues were in fact related.

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Fantastic! Glad it fixed your issues. :slight_smile:

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Well we had the same problem and tried to upgrade to 4.12.5 and it fixed nothing.

Blend Weight still read as a Boolean, (0=off 1=on) with no blend result in between.

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Hey, I just ran into this problem as well. Has anyone come up with a solution for this yet? I need an area to fade into light over the course of a few seconds using the Timeline node to adjust Blend Weight from 0 to 1. But it’s just on/off, there’s no blend right now.

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Same problem here…

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Hey Guys,

This actually isn’t a bug. Ironically the “blend weight” feature mentioned in this post actually is the bug. What the OP is seeing is the material instance’s distortion texture fading out to the master material’s distortion texture. In other words the material instance’s settings are blending into it’s master’s settings. It just so happened to work well with this particular case.

The intended workflow for this type of effect is the following. If I have a frost effect postprocess effect and I want it to fade out based off blend weight then I need another postprocess with another postprocess material instance based off the same master material as the frost effect. Except this material is the completely faded out version and is essentially just SceneTexture:PostprocessInput0 plugged into emissive color full blast. Alternatively you can just make a copy of the frost postprocess material instance and change some parameters around and it will fade into that. So basically blend weight is intended to fade between postprocess materials. If there isn’t another post process material to contend with it will just turn on and off.

I hope that clears things up.

Ed

1 Like
15

Latest answer just solved my problem ohhhhhhhhhh happy happy so happy
I don’t really understand but I caught the eureka moment!!!
Let me guide you lost soul–

  1. Make sure your father material has an ultimate exposed parameter that blends the PP effect with scene texture
  2. Set the default value of the Param in father MAT to ZERO
  3. Create an instance MAT and set the value to ONE
  4. The blend value in PP volume now magically works!!!