# Curve Projection

#1

Hi guys,
Please need some help, I am building an automated feasibility calculator - and need a little help.
I need to get my building footprint, I solved it already for simple geometry but to make it really universal I am looking for some free form solution geometry.

So I modeled some random geometry

And started doing magic in dynamo…

I got to the point when curves projects to the surface (it gives warning but curves are there - so whatever)
Problem is that projection give Lines and NurbsCurve and here I am stuck with it…what to do next…I tried to use NurbsCurve for surface patch - wont work.
Also same with lines. Goal is to somehow make curves from all this - make surface by perimeter curves and than calculate area.

#2

Hi, I run a test joining 3 lines and a Nurbs. The strategy is to recreate the curves from points and then use Surface.ByPatch.

1. In the upper part I used PolyCurve.ByPoints. When you create points at parameter, use a range from 0 to 0.999, otherwise the end point and the start point of your curves overlap and it doesn’t work.

2. In the bottom part I used NurbsCurve.ByPoints

Both cases are not perfectly accurate to get the real area, but if it’s a feasibility study, it might be enough. Of course the more points you use, the more precise it is.

PS. If I calculate the area in Revit, I get 273.778

#3

Just as an FYI you can use a little math to get rid of those awkward overlaps and additional points.

#4

Thnx for reply, yeah thats interesting approach, I thought about it too - but unfortunately that little precision is a deal breaker for me - because I’m doing this to convince managers at my new job (I work for a developer) to invest time and money in revit - and first at what they will pick is why they should spend money on something what is less precise than doing it oldschool (autocad+excel), in practice nobody would care about some 0.2 m2 at feasibility, but first I need to show them some “revit magic” to convince them to even think about it

#5

sorry didn’t understood…what it does? Sorry I’m new to dynamo

#6

Check out the Primer as it explains a lot of things you’ll need to know when learning Dynamo. This sequence is essentially stepping 1/10 ten times, or [1/10, 2/10, 3/10…]. This is helpful for continuous curves because it gives you n number of steps evenly.

#7

I don’t know that the miss distance was 0.2 square meters - coulda been 0.2 square feet. Both of which are likely less than your construction tolerances, which is likely something they should also be taught (if they don’t already know). Most developers I have worked with round off to the nearest 10 square for feasibility studies.

#8

I see your point, but if I had to buy Revit only to draw some polylines and calculate their areas, I would not buy it. We could talk for hours about benefits of Revit, extracting lines from free form solid to get areas is not one of those. If you want to impress them I would leverage on something else

#9

Dynamo studio is comparatively inexpensive, and could fill that need as an alternative to a full Revit build.

#10

No it’s not about extracting lines - this was just one part I can’t solve, this thing should work more as a complex feasibility tool. Where you can model some shape on the property and it will calculate you all the data for company to take a decision to invest or not to invest in property. I figured it out somehow (but only fot orthogonal geometry, buy I want to make it universal to give our arhitecture department more freedom in designing), right now I am figuring out how to implement cost estimation in this…probably cost people will not like this because I will make them useless