Placing structural columns on grids with dynamo

I’m trying to automatize the structural column placement with dynamo but I’m facing a problem that I hope someone else may solve. I’ve created a perimeter in Dynamo where the columns have to be placed and then I’ve divided this perimeter in points, which represent where the columns have to be placed. After this I’ve created an offset of the perimeter and I’ve divided it in points, in order to link the points from the two perimeters with lines. With this operation I can place a structural grid in each line.
Now I could insert the column directly on Revit, but I would like to do it with Dynamo. This task is very easy when the perimeter is linear, I can manage the placement with familyinstance.setrotation. But I don’t know how to do something of similar with perimeters that are circonferences or quarter of circonferences like in my case.

You’ll need to get the tangent or normal at the point of the guideline, and find the angle between that and the control angle of the column (could be X or Y axis depending on how you want the column to interface with the curve).

Jacob, thanks for replying me. I was working at another script in the meanwhile but now I would like to solve the issue with the script I shown above. I think that getting the normal point of the column is the only way, but how can I do it? do you have some advice?