Changing terrain height super slow whith grass

Unity Engine
1

I use the built in terrain engine in my game and have implemented basic digging which works very well for me.
Isuue is when i decided to add grass to my terrain, now its really slow do dig even if i only modify a single terrain point like this (part of code):

float[,] height = new float[1,1];
terrain.terrainData.SetHeights(posX, posY, height);

This makes the whole game lag for around 1 sec or more (hard to tell) which i find very strange considering the small amount of terrain i modify.
Without the grass it goes pretty much instant, why is it so slow?

2

Anyone?

3

In case anyone else have this problem i just want to say that i did a bug report on this and they responded that its a bug and will be fixed in a later version of unity.

4

I just now saw your post, or I’d have tossed in my $0.02.
Anyway…I seem to get this when I have a lot of trees on the terrain, interesting to see that you found it is a bug. Thanks for investigating this.