Translucent material + RayTracing

[Al_Bueno]

Hello!

I use to have a good translucent material I use for blurry glass, (as you can see in the image 1). But now I´m trying to change to raytracing, and I´m having problems with the material, that apparently does not show at all ( meshes with this material have this checker material look, as you can see in the image 3.

I think the problem has to be with the “spiral blur-scene texture” node in the material (image 2), because when I remove this node the material shows in the mesh (but obviously without the transparency) Also when I open the material in the “ray trace mode”, I get this error window (image 4)
So the question is, it is possible to achieve a translucent material with raytrace? What am I doing wrong?

[RealVis-Studios]

In 4.25 there is a new shading Model for Glass which is working with Raytracing.

[Al_Bueno]

@PrHangs

In 4.25 there is a new shading Model for Glass which is working with Raytracing.

I suppose you are talking about the "thin translucent "mode, but still, I can not set the blur spiral node (same erros I had with previous versions), and I can not find a way to give this blur milky effect…

[Al_Bueno]

@anonymous_user_5d2d3469

Raytracing+Translucency does not play nice for seemingly absolutely no reason, horribly bugging and doing random errors for seemingly no reason, a half fix (Its still a buggy mess) is to disable refraction under raytracing translucency, which does fix some problems, but it still will just screw up for seemingly no reason. The best solution is just turn raytracing translucency off and just go with turning up reflection capture res to 256 and making it try to almost perfectly fit the rooms (Use box reflection captures) with local captures for heavily reflective areas (Glasses full of whatever liquid, lakes and puddles, Glass, etc)

Edit: Also, use r.RayTracing.Reflections.ReflectionCaptures 1 for a free raytraced reflection bounce, using the scene’s cubemaps (When available), its not as good as an actual bounce but with well done cubemaps after a single bounce nobody will tell or care.

Thanks for your post. I tryed also that, but still the material shows with the default checker texture, and apparently the problem is the spiral-blur node; the moment I remove this node I am able to make a glass, but not a blurry milky glass…

[virtualHC]

@PrHangs

In 4.25 there is a new shading Model for Glass which is working with Raytracing.

I can’t get Thin Translucency to work with Raytracing. There’s no color being rendered at all. This is what I see (left, inside the raytraced scene, right, the material preview).

[gab_pek (4bstr4kt)]

I have the same issue, I think nvidia’s hybridTranslucency should solve it.

https://docs.nvidia.com/rtx-dev-ue4/…html#features

Share the results if you got it working.

[etfnehme]

I also have the same issue, I have submitted this as a bug.

The Unreal Engine Issues and Bug Tracker

[AdamRK]

Hi Guys! I found the key! atleast an alternative method.
so Instead of SpiralBlur I use a node what is called a SceneTextureAverage node.

Now I can make my glass blur again.

aaaanddd now I’m stuck again that my glass don’t receive shadows. only cast them.

[Dan_Lauer]

I’m having a very similar issue with raytraced translucency. And if I try to combine it wiith translucent shadows or raytraced reflections either of, or through translucent objects things get really weird.

Interestingly, I also do a good bit of work using Maya and the Arnold renderer. Arnold recently began supporting GPU raytracing, and of course it is significantly faster. But, transparent shadows are not working right, so any scene I make that requires that I will switch back to CPU raytracing. So, I’m beginning to think that the problem is actually in the GPU hardware or the OpenGL API.

[virtualHC]

In the new features announced for 4.26, support for Thin Translucency appears as an improvement for ray tracing: https://portal.productboard.com/epic…g-improvements I just tested it and it doesn’t seem to work (it looks the same as what I posted earlier). Has anyone had any luck with this?