Screen Aligned Material

[joshuamkerr]

I'm just coming to the end of a render and hit a stumbling block relating to a texture that I need to remain facing and scaled to the viewport.
It's part of a composite where a plane is placed in the scene with a image sequence playing.

The closest solution is to use the ScreenPosition node in the material editor. When the ViewportUV pin is plugged into my texture UVs the image looks fine in Unreal but octane doesn't render correctly.
https://drive.google.com/file/d/1_waNMZ ... sp=sharing
https://drive.google.com/file/d/1QwX5je ... sp=sharing

The PixelPosition pin however does give me a result in octane render but if I use this method I can no longer defocus. No matter what my lens settings I wont be able to pull focus to another object.
https://drive.google.com/file/d/1K35deF ... sp=sharing
https://drive.google.com/file/d/1K35deF ... sp=sharing
https://drive.google.com/file/d/1Jp2R6c ... sp=sharing

I want to know if there is a way to do this that will work or if this is yet to be implemented into octane render

All the best
Josh

[ChrisHekman]

Two things are happening here.

The first thing is a bug in the material conversion where ViewportUV and ScreenPosition are not working correctly in the plugin.
This is a bug and will be fixed in the next build. They should mirror unreal behavior in the next build.

The second thing is that ViewportUV and ScreenPosition will be the same for defocused samples, and focussed samples. Which means that you will see the texture through the defocus blur.
To fix this you need another function that unreal has: "ManualWorldToScreenUVsTransform". However this function does not currently work in the plugin for the same reason as above.
It will be fixed in the upcomming build.

[joshuamkerr]

Hi Chris,

Thanks for the response and good to know you're looking at this for the next build. Do you have a release date in mind?

The texture defocuses fine in the unreal viewport when using the viewportUV pin, but as you say it doenst work yet with octane.
I had a look at the "ManualWorldToScreenUVsTransform" node but it gives some odd warping in the Unreal viewport so I'm probably not using it correctly.

Hopefully it will all play nicely soon.

[ChrisHekman]

Hi Chris,

Thanks for the response and good to know you're looking at this for the next build. Do you have a release date in mind?

The texture defocuses fine in the unreal viewport when using the viewportUV pin, but as you say it doenst work yet with octane.
I had a look at the "ManualWorldToScreenUVsTransform" node but it gives some odd warping in the Unreal viewport so I'm probably not using it correctly.

Hopefully it will all play nicely soon.

Hopefully early next week. We are working on couple of other features/issues.

[joshuamkerr]

Hi Chris,

Great to see the update has been released and that those nodes are working.

I have most of these things working now but am encountering a depth of field problem when using the "ManualWorldToScreenUVsTransform" node.

My translucent plane is now inherriting the DOF of the nearest object behind it rather than where the focus is set. This makes it impossible to match DOF with the image I'm compositing.
It looks correct in Lit mode but not in the octane viewport. I have included images below.

https://drive.google.com/file/d/15GOgGh ... sp=sharing

https://drive.google.com/file/d/1_YnNeJ ... sp=sharing

I am aware of these sorts of translucency issues within unreal but have not encountered it in octane. Hopefully there is a fix.

[ChrisHekman]

I cant recreate your issue. I am getting expected results with ManualWorldTOScreenUVsTransform.
Would it be possible for you to send me a small repo scene that shows the same issue?

[joshuamkerr]

It seems to only be an issue when the camera icon is not selected in sequencer.