Bug: BaseParts are scaled in the opposite direction when resized with the scaling tool

(note: replies may not make sense with this post as I have edited it for engineers to replicate and to hopefully patch this bug in Roblox Studio)

Description:
When using the scaling tool built into Roblox Studio, the part is scaled or moved in the opposite direction at a fraction of the distance in relation to the scaling.
While this effect is much more prominent with smaller parts (at-least one axis smaller than 1 stud), it affects parts of all sizes and results in small gaps between a lot of parts and models and parts becoming disconnected to the spacing the developer intended on.

The plugin Studio Build Suite offers alternative part manipulation tools to those built into Studio, and their scaling tool does not have this bug, and is the only way I am able to continue modelling in Studio at the moment.

Expected behaviour:
The part should only be scaled in the direction it is scaled, and all other vertices of the cuboid selection box should remain in their exact position. When scaling a typical part, only the vertices of the face being scaled should be moved.

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When I first noticed the issue:
While I first noticed this issue in December 2023, I have noticed over the years that I’ve had many issues modifying old parts and models in old experiences, as they are for some reason misaligned or have gaps when moved back to other models that should be on the same imaginary spacing grid. This may be caused by the same bug as I am not certain when this bug first started.

This bug may be an issue with the newly added pivots, and the pivot may not be perfectly centred, especially for parts with 3 decimal places in their position or scale where the pivot position does not have enough decimal places to be precise.

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This is incredibly disruptive to modelling in Studio, or scaling any kind of part, union or even meshes, as it results in loads of tiny gaps and models and parts being misaligned.

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Replication:

  1. Open any experience in Studio, I have replicated this in default experience worlds.
  2. Create a part and scale it down so that atleast two of its axis are less than 1 stud in size and the other axis is less than 5.
  3. Duplicate the part (this will help to display the disposition)
  4. Scale the duplicated part in a direction while maintaining your camera near the opposite face to the direction the part is being scaled in. If you continue holding click on the scale handle, you will be able to see with the transparency that the part has been shifted in relation to the original part (the one the second part was duplicated from)

While this bug affects smaller parts at a greater rate, it affects all parts at a rate linked to the distance scaled and inversely linked to its size.

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An example:



This part is 1200 and 1500 studs in the x and z axis away from the origin (0,0,0) of the workspace.
When I scale it in a direction, it slowly scales in the opposite direction, when it shouldn’t be. This is a huge issue as it means it is impossible to properly scale and move parts so they are properly aligned, and this is an issue at all scales, not just the scale I am using.
(Note I am not holding shift, even though holding shift is meant to do this equally.)

Can you send a video of the issue or more screenshots? I don’t completely understand your issue.

Do you know of any gif creation tools I can use to display the issue? This is clear to me that it is a bug and I do not have access to the forum channels for bug reporting.

You know when you hold ctrl and you scale a part, it scales in all directions? Well, when I scale the part without holding ctrl, over a long distance of scaling, it very slowly adds a few pixels in every other direction, so over a large distance, the part becomes completely shifted from its correct position and size.

Here is the bug:


As you see in the first image, the part correctly overlaps the wall on the left, but in the second image, as it is scaled to meet the other wall, it slowly scales in other directions when it SHOULDN’T be.

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Ah, I understand now. Does this happen when scaling a part in one direction only?

This IS me scaling it one direction! holding CTRL to scale in all directions behaves as normal.
Are you able to replicate this on your end and are you able to report this to the studio bug channel?

this part is only 1200 and 1800 studs in the x and z axis away from the origin.

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Oh, my bad. I got it all mixed up.

I’ve never experienced this issue before, probably because I build on a bigger grid and use plugins.

In the future, I would highly recommend building on a better grid like 1, 0.5, 0.25, 0.125, etc and using the resize align feature in this plugin.

I’m not able to access my computer right now, so I can’t.

No, I’m not a regular either.

Zamn what are you building? A train game?

I do not have a choice to use a larger scale grid, and either way, this bug should NOT be occurring in the first place! This bug still occurs regardless of the scale.
Shame you don’t have the ability to report this, I guess I’ll just hope someone who can sees this post.

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Plugins may be your best option here.

Plugin for what? Basic movement tools? That’s pretty shameful for Roblox where such a bug exists within the PRIMARY tools to the point where a plugin is necessary.

Do you know of any plugins that you recommend for this?

No, a plugin to streamline the building process by being able to scale part faces to another. It isn’t necessary, but it makes things a lot easier.

I linked one in my earlier reply.

But that plugin is not a replacement for studios part manipulation tools, and would only help in a minority of cases, which excludes this one

From what I understand, the plugin I suggested would fix the misaligned part. It may not fix the bug, but it may be the best option you have right now.

Regarding plugins that replace the default building tools, I can suggest Studio Build Suite or F3X.

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SBS seems to not have the issue, although it is hugely sluggish to use compared to the built-in tools in terms of switching between modes and the handles are very oversized and out of date.

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I have now rewritten the main post as I am now aware this is a bug and how to replicate it. It seems to only be an issue with the scale tool, and does not seem to affect the movement tool. When using the scale tool and scaling along a certain axis, it scales in the opposite direction on the same axis a fraction of the amount, and this scales non-linearly the further the part is scaled. While I am using 0.025 for my scale to grid, I have also tested this with much larger scale to grid sizes such as 1 and 10 studs, and the issue still occurs at the same rate.

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Good to know. Thanks for adding this.

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I HAD THIS SAME EXACT BUG! A long time ago I was working on a game for my group, it used huge parts, and each time I edited them (scale, or move) they would offset themselves. It was so annoying.

Guess it’s not fixed yet.

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Sounds like the bug may be caused by the pivot not being centred. The pivot is a relatively new feature that defines the point in a part in which it is scaled/rotated about. If you select a part, go to [Edit Pivot] and move the pivot towards one edge, then scale it. You’ll see it will no longer scale uniformly. To fix it, just go to [Edit Pivot] and then the unlabelled [Reset] button and it should scale properly.

I have not edited the pivot at all, so the pivot not being centred is a Roblox-side bug, not a fault of mine.

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