This bug occurs in Roblox Studio when using the Terrain Editor. When the smooth tool is selected and base size is set to 1, it behaves like the erode tool at max strength, eating up the terrain quickly. The strength is not affected by this. Currently unknown when it originally began to occur, but this happens as of June 4, 2020.
Repro
Open any place
Create any sort of flat terrain using Generate or Add Tools
Switch to Smooth
Set the Base Size to 1
You will see that the terrain erode quickly.
Additional Notes
Setting the Base Size to 2 may produce similar results when dragged to a certain time, while setting the Base Size to 3 or above behaves as expected. This bug affects the ability to smooth out finer details in terrain in a smaller scale.
I was also gonna post a bug report about this. It really bothers me when I try to smoothen out a hill and it just destroys the hill rather than smoothing it out. I can report this happening to me as well. I’m on a MacBook Pro 2017
Major support. It’s done this way because the smooth tool will make the brush look like it’s surroundings.
If the brush is near a cave’s mouth, for example, it will chip away at the mouth since the brush detects empty space. Similarly, a hole in the ground will be filled because everything around it is filled.
However, on a thin, empty expanse of terrain, the smooth tool will not create terrain because there is nothing around it that tells it to grow, and will erode since below it there is an empty expanse. It will want to emulate that.
This, for me, is especially problematic in terrain generated by a hieghtmap. It’s so thin that I can’t smooth it out.
This needs to be fixed. ○︿○