Make glass work with transparent objects

As a Roblox developer, it is currently not feasible for me to use the glass material in my games, because the material does not work with other transparent parts. For example, if I place a part with 0.5 transparency in front of a glass part, the transparent part will be invisible.

This so-called ‘bug-feature’ of the glass material affects particles, water, translucent parts, UI, and all sorts of visual effects and transparent objects in the engine.

In some Roblox games, this may be just a minor eye sore and not an issue. However in larger games or games that have lots of windows in their maps and/or lots of translucent objects / particles in game, using glass will totally ruin the aesthetic of the game.

I am aware that some people use glass for the sole purpose of making transparent parts invisible. As such I propose that Roblox ‘fixes’ glass (makes it work with transparent objects) and creates a separate material or some new class with the sole purpose of making translucent parts appear invisible if looking through them.

If Roblox is able to address this issue, it would improve my development experience because I could use the Glass material in my game without having to worry about deteriorating how my game looks when it is viewed through the material.


Huge support. As fun as this bug is, it certainly makes the material unusable in the majority of normal use cases (like… Windows for example). Only very specific edge cases, like portals, benefit. We all know which is more common.

A fix was supposed to be on its way when the material first released too.


I completely agree with this post and @Aotrou’s response. Fixing this would definitely allow developers better control of unique game aspects to make richer environments. I support this.


This behavior of glass is extremely unattractive because in my game players have the ability to build. They can make glass parts and literally just see straight through the ocean.


This issue has been mentioned at least 100 times but I feel like I have to bring it up again. It’s really frustrating that you STILL can’t see decals and surfaceGUIs through the Glass Material. It’s 2019, and we’ve got ShadowMap, Realistic Grass and much more but we are still forced to deal with this issue for a year and a half. It really is limiting the realism of my game, and is making me resort to using plastic but with a 0.5 transparency and I’m sure others would have the same concerns as me.

This is a comparison:

Honestly, it might not be the biggest of issues on a minor scale, but on a large scale it certainly is. I hope this will reach the right ears, and hopefully it can be changed for good.


Still never used it since it came out. It is also sad that we have no other means of achieving the fresnel effect and refractions without having half of the map disappear.


Yep. I have also not used it since it has come out. It really disappointing me that it’s been months and nothing has been done about this. The glass material is completely unusable because of it’s current functionality.


What I don’t understand is why they didn’t just use a screen space effect. I would much rather deal with edges not being rendered in some situations than having entire models disappear. What they still can’t fathom is that a lot of detailed models have opaque textures. Cars have windows, houses have windows, water is… water? You cannot just go and say “eh… it’s good enough”, especially with the hype they stirred around this, only to have it forgotten by everyone.

If I am mistaken and this is in fact a screen space effect, then why are opaque objects not rendered?


Might have been due to them not wanting to add it for time / performance reasons?


I don’t know what they exactly used, but screen space shaders are barely affected by the scene’s complexity. They take the information already present on the screen and apply an effect based on surface normals (that’s why screen space reflections can only reflect what’s on your screen, so you get those weird missing bottom face artifacts in water reflections or blank spaces on your screen’s edges and the same applies to other screen space effects). The thing that really makes them intensive is a higher resolution, but that generally makes the entire rendering pipeline a hog.

What makes screen space perfect for refraction is that it can never point at something behind the camera, unlike mirrors. This means that only extreme cases of concave faces would cause issues.


I was making a speedboat when I noticed that terrain water disappears when you view it through glass.

I messed around and found that it only does this when your graphics quality is set to 8 or above and shows when it’s 7 or below.

Most likely this is a bug or it’s intentional. If it is intentional, I’d like to know why that is the case.

Graphics at 10

Graphic at 7


As a Roblox developer, it is currently too hard to make high detail things with glass involved, because glass doesn’t allow for decals, surface guis or billboard guis to be seen through it, and glass is one of the only materials that can be used to make high quality windows. So, I am requesting a feature where glass has an option to allow it to render the things listed above that are not rendered while looking through glass.

If Roblox is able to address this issue, it would improve my development experience because I could make better builds with glass and decals and interactive guis and make my games look a lot more in detail. For right now I might have to use transparent plastic, which doesn’t have the same cool texture and effect as glass.


Terrain water is invisible behind the glass material, but only when graphics quality is above 7. This seems counter-intuitive, as higher graphics quality settings are supposed to make the game looks better, not worse. It’s too bad this happens because I really like the refraction effect glass has. I can’t use this material until it’s fixed because you can see through the ocean when you look through windows.

Graphics Quality 10:

Graphics Quality 7:

EDIT: It’s been over 2 years since, and it’s still not fixed.


I am once again bumping this issue

This bug makes using the glass material infeasible in games that heavily rely on SurfaceGuis (among other non-opaque parts)

With Glass

Without Glass

Im not bash the old drum of this being a three year old issue but, I’ll just say this:
Roblox have made a lighting engine with really advanced shadows, I’d assume thats a lot more performance intensive than rendering a few GUIs through a material.

Obviously, I’d love to see some benchmarks from the Roblox Engineers themselves to prove if it really is a challenge, however we’re not seen them


I always use Plastic instead of Glass for this reason. The way it filters color is useful, but the distortion effect isn’t practical for games in its current state.


Agreed. I think there needs to be a solution to this issue since I still haven’t used glass because of this. I also wish I could see particles and other transparent objects through glass.

The best thing for roblox to do would be giving us a way to hide transparent things like with glass while also making the material function like it should.

I really hope this gains more traction again. Get your friends to post here, I’d like to see if Roblox is willing to finally fix this.


It’s been awhile now since i’ve encountered this bug, and I am still very suprised that this isn’t fix yet. Not only does transparent objects not get rendered through glass, but other visual instances don’t get rendered through class too. Such as rope, particles, guis, etc.


Indeed. It is mid 2021, several years later, and I still refuse to use this because frankly, it makes something look awful. There are so many cool things I could make, and others could make with the glass material if Roblox fixed it.


Went to use glass on space station windows recently and realized it would run all the glowing and semi transparent parts I have… I am pretty sad this is still an issue.


With the new material service system, I am wondering if now is the time Roblox can finally fix this issue while ensuring that those who want to use glass for it’s transparency effects are not screwed over.