Negate Part changes its mesh

[mutrix]

Alright so basically I want to make a road border, so, I took 2 cilinders, on with a smaller radius and then negate it and union it with the bigger on, so I get like a “ring”

So before negating it it looks fine, it is the same as the bigger ring but smaller, but look what happens when I negate it

It moves, the mesh changes, it is not relative and proportional to the bottom ring anymore, it just changes, and rotating it doesn’t fix it

So if I union it I get something like this

Any way to fix this? any information is appreaciated

[mutrix]

Also, if I try to negate another part anywhere, it changes to

[MechanicalCore (dev)]

Well honestly speaking there’s not much you can do about that, since Roblox cylinders are not perfect cylinders and they get a different triangulation when unioned.

If you want it to be perfect, I suggest you make the road in blender and import it into Roblox. If you aren’t good with blender, learn it, it will help you in the long run. (and if you aren’t good with it, how did you make that bunny hut in the background? )

If you don’t want to use blender, you can use this plugin, Archimedes two. This is a really great plugin. If you build a lot, you will find more and more ways that this can help you in making arches, circles, and what-not.

Either way, good luck.

[mutrix]

Well I do know how to use Blender I never said I didn’t
Thank you for your ideas, I will consider it!

[Astr0Derp (Astr0)]

That’s unfortunate. No idea how to fix that in a direct way.

Since you are relying on those edges to line things up, another thing you could do for a work-around is to make a regular polygon instead of using the cylinders. An easy way to do this is to make a rectangle Part with length of 2 and use a polygon calculator (like this one) to figure how how wide to make it. Then copy/rotate the Part to make the shape.

For example, let’s make a 10 sided regular polygon. Since it’s an even number, we can use one rectangle to make opposite sides of the final shape.

1. Make a Part with length of 2 and depth of 0.1.
2. Change polygon setting in website to n=10, calculation using “inradius r”, and set r=1
3. Make note of the calculated values:
   • “side length a” will be the width of your Part
   • “exterior angle y” will be the snap value you use for rotating the Part when it’s copied
   • “inradius r” is the distance from the middle an edge, but we doubled this for the length of our Part since it’s supposed to stretch to both sides.
4. Group the parts into a model and scale it up.

That’s it. You can do it with however many sides you need. From there you can union the parts into a shape, or keep it separate and scale down the rectangles toward the outer edges so you just have a ring (or rings) instead of a solid polygon.