MeshPart DoubleSided

Hey Developers,

Just wanted to drop a quick note regarding DoubleSided for MeshPart. This feature has been enabled on all platforms.

In Studio’s MeshPart properties, you will find “DoubleSided” in Appearance category:
image

By default, DoubleSided is off and you only want to enable it for meshes that will benefit from this feature, for example meshes that are modeled with (single sided) cards, such as leaf, hair, cloth.

Example:

The tree leaves are modeled with single sided cards.

With MeshPart.DoubleSided disabled some leaves are missing since they are back facing the camera.

With MeshPart.DoubleSided enabled, both faces of the leaves are rendered.

Thanks for reading and let us know if you have any feedback!

394 Likes

Are there any performance implications for enabling this? Nonetheless I find it to be a pain to model something from the 2 sides, so this will be of help. Thanks

51 Likes

Just yesterday I was having a problem with this and now they added doublesided meshparts lol

35 Likes

Love to see new features come to MeshParts. What would perfect them for me would be the ability to change MeshID in-game vía script. Since the feature has recently become available to plugins, are we going to be able to expect this feature for scripts too?

10 Likes

If it’s them basically toggling backface culling then it should be more performance heavy, in situations where faces would’ve otherwise not been rendered.

7 Likes

SuhhWEEET!
It is TIME my In Nature’s Realm showcases become A LOT more optimized. 300 million + triangles cut down to less than half or so. I am excited

13 Likes

Awesome! I’ve always hated having to dupe geometry with something like Blender’s Solidify modifier because it just wastes polygons.

Thanks for this feature. I already have many use cases for it.

18 Likes

300 million tris? Are you building the entire planet at 1:1 scale?

22 Likes

LOL I make realistic nature assets and make showcases with them. It piles up quickly not using cards!

8 Likes

As cool as this sounds, isn’t this essentially the same as duplicating faces and flipping the normals performance wise? I would imagine this is just so you don’t need to worry about doing that within the modelling software since duplicating faces and having to go back to make changes can get troublesome sometimes, pretty cool though nonetheless!

4 Likes

Does this also allow for properly sorted vegetation? If not, when can we expect that update to be pushed out… or is it already and I’m just missing out?

1 Like

Also very interested in the performance implications of this!

I know other engines do this as well - is the intent to reduce the work done by the artist or is there also performance benefits from the rendering side?

7 Likes

Definitely a good update. I’ve had friends who’ve had lots of troubles with this and hopefully, this solves all the “invisible mesh” building support topics.

@R0bl0x10501050

After doing some testing, the triangle count doesn’t appear to double when DoubleSided is set to true despite being able to see both sides of the mesh. I’m not sure if there are any hidden performance impacts but this is an incredibly useful feature and I can see many use cases for it outside of foliage!

5 Likes

I’d like to know performance-wise and how well it does with Roblox games and inside studio for development and gameplay, saw this FFlag get activated an hour ago before, and seems neat.

I feel like this might be a game-changer for developers who use Decal or Textures for vegetation leaves so it looks more realistic, I’ll be sure to use this for an upcoming project and more experiments for this.

Is this live at the moment or in Beta in Roblox Studio?

3 Likes

Can’t wait for noobs to mindlessly use this feature as a “fix” for issues with inverted normals… :upside_down_face:

3 Likes

The performance impact must be less than doubling the number of triangles

2 Likes

this is a good feature it actually fixed one of my meshes up

Before

sword blade only goes on one side only

no texture
image

with texture

After

Sword blade goes both sides now

no texture
image

with textures

Thank you for this update!

4 Likes

No. It didn’t fix it, it made it worse… :man_facepalming:
The “fix” is a lie, it’s just visual. You don’t need the geometry to show from the inside. Invert these normals so they face the correct way.

cough

Anyways, here’s how to fix it:

Image-heavy instructions

This is how your mesh looks like:

If you toggle this setting, you will be able to see it how you’d normally see it inside Studio:

You can also more clearly see which normals face the wrong orientation by toggling the Face Orientation overlay option:


(@DieSoft figured I’d mention you here, since you mentioned the face orientation indicators, which are a bit hard to use in some cases, not sure if you’ve known about Face Orientation toggle)

Now, to fix it you can either select just the part that was showed as red, and flip it manually via the Alt + N hotkey, or you can just select the entire mesh and hit Shift + N to let Blender figure out which face should point where:


And then you can see the result, all faces are blue (meaning they’re facing the right way), and your mesh no longer appears “hollow”


16 Likes

If this “fixed” your mesh, it’s probably still broken, just less broken than before (it now looks correct but is rendering extra geometry that doesn’t need to be rendered at all)

13 Likes