Decals are "squished" and look different on spheres

Reproduction Steps

Put a decal on a ball shaped object or a object with a SpecialMesh in it.

Expected Behavior

Decal on the sphere should not be “squished” inwards.

Actual Behavior


Sphere is squished inwards towards the center of the face the decal is on. I do not have an image of the previous behavior (because… why would I? It’s really specific).

Issue Area: Engine
Issue Type: Display
Impact: Moderate
Frequency: Constantly
Date First Experienced: 2022-08-12 00:08:00 (-04:00)
Date Last Experienced: 2022-08-13 00:08:00 (-04:00)

22 Likes

I believe in part that this has to do with the UV Unwrap of the mesh.

One issue prevalent on cylinders is that the UV for one of four curved sides is actually rotated upside down which leads to a decal showing up inverted, probably a mistake when the original mesh was created by ROBLOX eons ago.

The best fix for this for your own personal preference would be to re-create the mesh, Create a UV map for it and customize the Faces Layout on the texture which gets saved with the main model. FBX files are fairly consistent for this too, if you use Blender or Autodesk Maya for the mesh and UV Mapping.

1 Like

To support what I’ve said further - This is a UV Sphere in Blender with 24 Vertical and 16 Horizontal segments.

When directly unwrapped in with the UV tools for Blender, the default Unwrap via Project from View with the face looks like this (without any straighting out the lines or so on).

Even when straightened out, the resulting decal would look skewed as the game engine has to fit each pixel of the image within the size of the faces provided by the mesh, according to it’s UV Map. This “squished” perspective of a section of the texture/decal on the faces of the mesh is expected, regular behaviour as the dimensions are not like that of the texture.

ROBLOX may not be able to solve this alone. This is equal parts ROBLOX’s meshes need to have clear UV mapping guidelines and developers utilizing textures need to be more attentive to the shape and scale of the mesh. If you were to skew/squish the texture according to the faces of the mesh it will be displayed on (say, using Adobe Photoshop’s or GIMP’s transform tools), it may not solve the problem but it could be less noticeable - on a mesh-by-mesh basis.

[EDIT]:
This is fairly generalized and I’m still learning about this stuff for my own game engine in university - there’s several caveats to be considered with the default “Face” placement of the decal/texture as well as UV Maps. ROBLOX has default behaviour for BaseParts, Unions and SpecialMeshes. When you create custom UVs and custom textures, you essentially help the game engine to unwrap and align the texture with all the faces which leads to better results.

I don’t know fully how ROBLOX handles the decal alignment to the UVs of each face of a part and specialmesh - e.g. whether it’s automated or specifically laid out with hard-limits built in by ROBLOX engineers so that decals and textures perform with mostly expected behaviors. Nonetheless, I would not consider this an engine bug given how meshes and textures work with game engines as a whole yet this is for ROBLOX Engineers/ Community Engagement to decide.

4 Likes

no offense but this is missing the point entirely. this is an engine bug, an intern must’ve botched the UV map on the default sphere as it’s almost completely different from how it was only 2 - 3 days prior.

there’s also another bug that came with this one, that appears to only effect certain devices. basically, when the client or studio is started, you have a chance to either run into the usual UV distortion sphere, or this second image i attached of a sphere with corrupted polygons. there are no steps to reproduce either, you simply open the client or studio. i am not the only one experiencing this version of the bug, two other friends have witnessed spheres with corrupted polygons also.
image

14 Likes

The wording here is more clear than the wording the original post gave.
Though I will state, it could either be the UV Unwrap or the developers are working on the rendering pipeline for studio and the player.

Another thing is, I can’t say for certain what’s causing this, it could just be the engine isn’t even accounting for the skewed faces with texture application. The skewed texture perspective does seem like expected behaviour for applying a texture in a space between four vertices but we’ll wait and see for ROBLOX in this case.

As for why I went into UV Maps. Overall, they’re a pretty good resource to look at so people can understand a situation like this. I do think they’re very relevant here and didn’t miss the point at all (as no point was made by OP). On further thought of the issue, there may even just be the chance that the UV Unwrapping / Texture Application itself could have been botched or may have been in the process of a bugfix during the studio update. An experienced engineer probably will look through the code soon too.

This is a really cool issue I’m (unexpectedly) excited to see in a real-world scenario as I’ll be able to include this in my university research for creating game engines.

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This issue didn’t exist before the update pushed
Guess an engineer broke something that will never be fixed lololol

Gyazo MP4

4 Likes

This literally happened to me a lot of times when I was working on my projects involving sphere parts.
I really don’t get why Roblox let this bug slide and other people didn’t took notice of the bug itself, except for me and my friends.
image


4 Likes

One weird thing I don’t know about for sure - this may in turn be linked to Graphics Mode (Studio Settings > Rendering > Graphics Mode).

This only appears for me when I revert to Automatic and DirectX personally. In Vulkan, I don’t have any issues at all with spheres, no matter how many times I try to bruteforce the issue to resolve. In Automatic and DirectX, it appears as shown here.

2 Likes

My friend has the same problem confirming this is probably a bug.

3 Likes

im literally having the same problem…
i want them to fix this.
image
image

5 Likes

Yuppers, Also having the issue. This has been going on for a while and roblox didn’t take notice of the bug and usually act like their not browsing our amazing creations. Usually takes 2 days or more to reply, and unable to screenshot because i’m on my tablet decice

Yeah, still getting the issue as well. Well, not this one

But every decal appears a little different on a sphere. This bug seems to have been when the CylinderMesh humanoid bug started happening, but I’m not sure. I’m also wondering if some MeshParts have the corrected old UV map.

I’m also wondering if the issue occurs with the Material UV maps, since I think (not sure) they’re different.

Other than that, not much else to say here, everything has been covered by the previous posts.


I never experienced this on my Windows 10 and Windows 11 PCs. Is this still happening? I cannot tell.


If so, they could’ve built studio without the new version, if it had problems. I do very much think that this is true. (But is it happening in the UWP app? No reports for that… yet…)


I would think that Roblox would eventually fix this. It’s not like the topic was closed yet or anything.

Because I’m helpful:

You can press the volume down and power at the same time to take a screenshot on an Android device, or on a Samsung, swipe your whole hand across the screen, like a scanner.

Roblox Studio is not on Apple.

Yes. This is how geometry works. Keen observation, BoojieQ.

Hi, could you send me a copy of the 1st & 2nd buggy place to investigate?

Also seem to be noticing that spheres are clipping through some parts that they didn’t previously - I’m starting to think this was a wholesale replacement of the sphere mesh.

If those spheres are part of Unions please verify that it’s not caused by this rolling out yesterday: Nonuniform Unions: Now Available on Production (could make unions increase in size and clip through geometry)

1 Like

The spheres are not comprised of UnionOperation objects, and are just made of standard parts.

As an aside, the clipping itself seems to have disappeared as of today.

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