Creating Clear LEGO Plastic in UE5

Hi! A newbie here. I am currently working on a project in UE5 in which I am designing a LEGO cinematic scene. I’ve already designed materials for everything BUT the clear plastic. After scouring the internet, I’ve arrived at a monumental realization: nothing exists (as far as I know). So, I came here asking for any ideas for a “cheap” way to create clear plastic in unreal.
Now, here’s the kicker. For starters, it can’t be a glass material, because the default glass material everyone says to use bogs down my frame rate from 48 to 6. And the shader complexity? It’s white, the most expensive shader possible. And besides, using the glass material on the plastic makes it look fake.

^^^^This is the look I’m going for. Notice how the material gets darker on the edges, where the plastic is thickest.
What’s really funny is that Blender can do the same thing and it still remains super-efficient:

So…any ideas? If it is impossible to do inside of UE5’s code, are there plugins for this?
You guys are the best!

Just FYI, I am basing this all off of this guy: Imagine: Developing The Winner of Unreal's Better Light Than Never
Somehow, he created a clear plastic (notice the car’s windshield:

He never shared his shader model for it.

My humble effort?


It’s pretty high though :slight_smile:

The moment you have transparency, you have a high cost.

If you use additive mode, and unplug the refraction, ti’s a little better

It might be considerably cheaper if you’re still using SM5.

For starters, it definitely looks better than mine! (Mine was literally white in the shader complexity view) What does it look like on your end if you don’t have refraction? (Clear LEGO plastic pieces don’t have refraction IRL)

I was wrong, you can use refraction in additive also. Still at the same ‘less than white’ cost :wink:


I like the way this is going. Is there any way to make those edges a bit more defined? If not no biggie.

You’d have to fiddle with it quite a bit, this is just my first guess

Using a little emissive

Looks good!
Three final things before I mark this as the solution:

  1. Will this material glow in the dark?
  2. Can this material have shadows cast upon it?
  3. Is there any way to add a clearcoat upon the material so it can be slightly reflective?
    (If 3 is impossible, no biggie as well.)

Hi all,

For your question about it being slightly reflective I’m reminded of this past roadmap item.

It’s unclear if they are referring to the Shading Model ‘Thin Translucent’ (Right below where you select Blend Mode: ‘Translucent’ in the Material Editor)

I forgot about the Thin Translucent shading model! :smile: Perhaps that is what I should be using!

Just to chime in on the subject. If you want see through plastic, you will need to have some form of translucency. The more translucent bricks you stack the worse the scene will run. So having multiple translucent materials stacked will cause a significant frame drop.

The additive mode is cheap and is probably as cheap as you can go.

I will only be using this material for windows, so it shouldn’t do too much damage.

1.Yes, probably, you have to manage that

  1. Not sure

  2. Same as 2 ( not at a machine right now :slight_smile: )

Best thing is to give it a go…

Thanks for your help, everyone! I’ll play around with the ideas you sent, try what works, and post what does here.

1 Like

So here is what worked for me: Basically I went with Astrotronic’s suggestion and went with full-on Thin Translucent Shading model:

This works really well for the plastic for two reasons:

  1. The Opacity parameter can change the ‘thickness’ of the plastic
  2. The material is reflective, which is a win

However, there are two cons:

  1. The material cannot receive shadows
  2. My GPU hates it dearly (very expensive)

But it works for now. Thanks again, guys!

The current product^^

With some imperfections it looks AAA: