I’m not sure if this is a bug or a known limitation, but I was playing around with the new UMG Background Blur widget and noticed that it does not work the same in the viewport and as a 3D widget.
If you have a 3D Widget with a Background Blur in it (and it has a value above 0), any area it covers will be opaque in the world. This includes transparency from images inside the widget itself. I was expecting it to blur the world behind it as it does when you add a widget with Blur to the viewport.
This limits the use of the blur widget pretty severely for 3D UIs/Menus since you can only use it on opaque images.
This is a 3D widget with only a blur widget in it, and a value of 1. As you can see it’s completely opaque.
Here’s another example but with an image under the background blur in the widget (in that example I resized the blur to be around the same size as the image).
I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates. Thank you for your time and information.
Rudy, thanks for fixing the link. Is there anything that can be done to change this from a “won’t fix” status? How does that get decided upon? Is it something done internally, based on demand or some other factors?
Hey JLBXB3, I’ve been looking at this for a few days and as I understand it, an entirely different methodology would be needed for 3D widgets due to how this [beautiful] 2D blur was designed.
I created a post on the forums a few days ago fishing for ideas how to create it and while nobody has responded, I’ve still been thinking through how to do this, in my spare time. I’m thinking it could work using either the SceneColor node or through a RenderTarget with some custom shader work to create the Gaussian Blur. All this to say, I think it’s entirely doable but I’m not 100% on the details of how… yet. If you want to work together to get it done, I’m all for it. Maybe reply to my forum post and we can get some more eyes on the problem.
For anyone else interested, I’ve done a bit more research into this and I just haven’t been able to find a good solution. In order to be used in UMG, the material domain type has to be set to ‘UI’ which means you can’t use SceneTexture or SceneColor nodes, one of which is required for every blurring method I’ve seen. From what I gather, these limitations are due to the order in which UMG is rendered and likely the same reason this isn’t built into the new UMG Background Blur effect.
Blast. As a VR developer, 3d widgets are critical, and this would be very useful. Please reconsider this, or perhaps, as another way around it, a proper implementation of gaussian blur in a texture/material workflow rather than using PostProcess materials?
This gaussian blur looks and performs waaay better than the PostProcess volume tricks I’ve been using. Can you post the math somewhere so I can try to hack a texture to do the same thing?
