Triangle mesh parallel with ground plane

Hello everyone, I made a triangle mesh for a double curved surface. Each triangle edge has a length varying between a set of 6 length of 50, 52, 54, 56, 58 or 60. I use LengthSnap (from Kangaroo) for this. However, I have one problem unsolved for the moment. I want to have the bottom edge of the bottom triangles parallel or touching with the ground XY-plane. Which is not the case now (as you can see in the picture). Does somebody have a solution for this?
Attachement: (23.9 KB)

Here you go: (23.7 KB)

AnchorXYZ lets you fix the movement of the base vertices only in Z, while still leaving them free to move in X and Y

Thanks again! @DanielPiker

I’m wondering something else. Would it be possible to get the mesh even closer to the surface? I know the deviation in every point from the mesh in relation to the surface. For factor 2 the mesh is already pretty close, but for example factor 3 gives a bad one. Especially in the points where the deviation is 11,33. (24.4 KB)