Making extrusions sit along a site/topographic model

I’m trying to create a site model of downtown Columbus (OH). More specifically, the arena district. I would like to have the site model also have topographic data, so that the buildings sit on top of the topography accordingly as the elevation of the site changes.

The buildings are simple extrusions, and I have a contour map of my site (includes elevation change), which is approximately 6000x6000ft for 2x2km. I have been experimenting with Grasshopper/Elk, as well as using a script to create a drape over the contours.

I need help aligning the various structures/buildings of the site to the topography. I would appreciate any tutorials, tips, and commands.

I have tried using the splop command and the flowalongsurface command but the issue with these commands were that the forms become distorted.

Is there a grasshopper plugin that would help me create a site model with topographic data and the buildings (and roads)? or an easy way to get all structures to sit atop and go along a site contour or drape, etc.?

I am having an issue akin to this person’s dilemma.

Hello - if you have a target surface/polysurface or mesh object, this may help: (3.0 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"


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Thank you. I will try this out later and see if it works.

I believe I would have a surface/mesh created from the contours, so hopefully the models can align atop said surface/polysurface/mesh like I want it to.

That said, do you have any recommendations for using Elk to model both the buildings and the topography at once/in one model?
Or should i make the topography model and the buildings separately and then use your Python script to put them on the surface?

Hello- I have no information about using Elk; for my deal, yes, it should work if you place your building where you want in XY and let the script adjust the Z.