Flowify is not working on imported DTM Surface

Hi,
I am trying to model a road onto a surface that I imported from a DTM. I use Flowify for creating road models because it allows me to make changes easily afterward. Functions like Drape break the roadlines into many small segments, which makes modifications later on very difficult.

The problem is that Flowify is not working as expected. I already converted the DTM into a quad-based surface since it was triangulated before, but that didn’t solve the issue.

The attached image illustrates the situation:

The imposed grid with a surface that I created in SketchUp.
The actual problem—the DTM surface where Flowify was unable to impose the grid.

If anyone has an idea why Flowify is not working, I would really appreciate your help.

Did you create the groups correctly? What error message are you getting? The photo doesn’t provide any of this information.

So here is a video of the groups. Unfortunately you cant see which buttons I used but I went on: Settings - Flowify - impose grid and before that I grouped all 3 groups into one. They are definitely right, because it is working on the sandbox surface. It has something to do with imported DTM.
And I dont get any error message when clicking on impose grid.

Without useful information about the model you are using, I tested with a model I created and it works as it should.

Which information do you need about the model? I am using the standard DTM used in Germany, with a 1x1m grid. I imported the DTM into QGIS and then exported it as an STL file to import it into SketchUp. After importing, I transformed the triangular grid into a quad grid using Quad Face Tools.

In the picture, you can see the entire terrain I imported. Currently, the terrain is still a triangular grid because I was experimenting on a smaller scale to make it work.

There are major differences between the photo in your initial post and the photo in your most recent post. Do you have a model correctly set up to be used with Flowify?