How to find part is in region?

I need to find part in region with whitelist, but my problem is, that it isnt classic region, but circle, that have center and radius, is this possible?
(sry for my describing skills)

Your question is a bit hard to go off, however do you have a circular region or just a normal region? What you could do is check the magnitude from the center of the circle, as that way it’ll check everything around it and also return if it’s in the circle or not. This would remove the need for a region as well, as it’d check if it’s in that sort of circular/spherical area.

I dont have anything, but radius and center and i need to find part inside circle definied by parametrs i have, at this i am total noob

That doesn’t make much sense, also I just gave you the answer. Is that not correct/ enough?

Its correct, but idk how to check it if it is in the circle. By

 local isInRange = (partsVector - center).Magnitude<=radius


Roblox only supports perfect unrotated quadrilaterals (squares and rectangles) with Region3 and related FindParts methods. If you want to make a circular method, really all you need to do is check the magnitude of the distance vector between a point and the origin of the circle.

If you want to use Region3 with an arbitrary shape, you’ll have to use a custom implementation of sorts that works on top of Region3. There’s a good resource out there if you’re interested which first casts over a Region3 and then downcasts to the region for further part filtering. This can help you make zones and all.