Drainage Simulation with coloring

Hey everyone,

I have a lot of problems with my drainage simulation and hope that someone can help me.
So first, I need to simulate a drainage with water going down some topographie (maybe that part already would work when my problem 1 and is solved?). Second, there shall be different coloring depending on how much water is at a place.

My problems: I have some grasshopper file.

  1. I can’t put a mesh in the input part. That one I created in another file doesn’t let itself being extracted and when I tried to use .obj files I could download from websites, they were 90 degree rotated and still nothing worked.
  2. How do I do that coloring stuff?

Sorry if those questions are stupid, I am new to C# and new to Grasshopper and I have absolutly no clue and am stuck for days now.
Thanks in advance!

Here’s my Grasshopper file so far: DrainageSim.gh (9.7 KB)

For the mesh orientation problem, use Rhinoceros to orient it.
If the script isn’t working it could be because there are not enough Vertexes on the mesh.
Here a sphere with 100 faces

Here 10000 faces