Any reason as to why 32 parts being unioned should be 177KB?


I’m not sure if there’s any solution to this or how to go about solving this but this union I made is composed of a mere 32 parts. However when saved to file is a whopping 177KB.

A build that I made which used this union turned out to be much larger(space-wise; 50367KB or about 50MB) than anticipated which was cause for concern as I wasn’t able to upload it as a model. Is there some sort of trick I can use to achieve the same result look wise without using so much space?


It’s because of the inefficiently in CSG/Unions. Try remaking that part using blocks, cylinders, and spheres. You’ll likely save a lot of storage space.


You’re probably best off using a mesh - Unions each save their entire history of unions/negates (to allow you to un-union them) so it’s not surprising they rack up large file sizes


I’m fairly sure they don’t. They just re-union up to the last step when you un-union something. That would be a terrible memory issue.


Unless I’m misunderstanding something, this still means that a union like the one in this post would have to store the info of 32 separate parts, rather than just geometry information. Otherwise you wouldn’t be able to completely separate a union back to the individual parts it’s comprised of


Oh for sure. I may have misunderstood you. I thought you meant it saves the new Union created each time haha.


I highly recommend the use of Blender to achieve what you want, once you start to understand the hotkeys it’s a great experience for creating things like these, especially compared to the system for creating unions.

Here is how I'd achieve this in Blender without the use of hotkeys

I quickly recreated a rough version of your model for this example:

  1. Select the Modifiers tab in the properties window.

  1. Add the Bevel modifier

The information in the properties window should now show properties of that modifier.

  1. Bevel segment value

Change the amount of segments you want to bevel to whatever you’d like, I chose four for this example. I recommend messing around with this to get the result you want, but of course be aware that setting it too high will create a high polygon model which would use significant memory.

  1. Smooth shading

For the result you want, I recommend changing the shading to smooth. To do this, navigate to Mesh > Faces > and scroll down until you see “Shade Smooth” select this and it should produce the result you want.

  1. Exporting the model

The model you now have should be what you wanted, to export this into Roblox I use this process.

Once you click on the FBX option, it should prompt you to save the FBX to your computer. Before you do this I recommend changing the scale of the mesh to 0.01 so that the model is not massive once imported into Roblox.

Once the scale has been set, click the “Export FBX” button and you should be ready to use your model in Roblox, using a MeshPart :slight_smile:

If you have any questions regarding this I’d be happy to answer.


This person is a genius.

Unions are bad, meshes are good.

I will share this fact with everyone as long as I live.


Ah hell, I’ve been dreading getting into Blender. Thanks for the help.


If you have any questions regarding it or my tutorial let me know!

I tried to make it friendly for people who typically don’t go into that type of stuff because I understand how confusing it’s interface is :stuck_out_tongue:

Also, if you want to mark the thread to have a solution so people can go into the thread expecting an answer, click the box with a check mark beside the “like” heart


If you could think of via Blender perspective, looking at something like that you could probably see there’s lots of vertices and faces which takes time to render, spheres are a lot of vertices being as smooth as possible.

You should get into Blender as meshes are much better if preloaded properly. Otherwise, they wouldn’t change that much as it would take as much time as it would for a regular union to load.


I’ve never had this issue, and I use unions all the time. :thinking:


I understand how confusing it’s interface is

Blender is literally the least-user-friendly program I’ve ever used. It’s horrible.

But yeah still good advice.


That was it made from blocks, cylinders, and spheres.