# Surface.pointatparameter

#1

Why I do not see on the surface points that generated?

#2

You will be making points here, but they’ll be outside of the extents of your surface…

0…1#n

0…1#n

• so that the points are on the extents of the surface - as when U=0.5 & V=0.5 this will give you the centre of the surface.

#3

Thanks I understand. One other question Still on the image I posted, how can I extract a sub-list to draw a curve on the surface in one direction? I tried with several commands but nothing …

#4

Daniele,

Have a look at the output of Surface.PointAtParameter. It’s a list of lists where each sub-list holds number of points equal to length of list supplied into V parameter. So basically each sublist holds points that if connected with a Polyline would give you a vertical line (U = X, V = Y). To test that you can plug those into Line.ByBestFitThroughPoints and that will create all of the vertical lines. If you wanted horizontal lines you simply have to transpose (grasshopper users flip matrix) to create sublists of all U parameter points. Because the output list is a three (3) tiered list (list of lists of lists) then to transpose the second tier list you have to feed it through List.Map. Please see the example below.

Also, to add to the previous question as to why when you create a list of points 0…6…#6 and they didn’t show up on the surface you have to understand a few things about surfaces. By default all surfaces in Dynamo (and Dynamo team please correct me if I am wrong) are re-mapped to 0-1 domain. That means that all UV parameters for any surface in Dynamo are always between 0 and 1. In other software (Revit, Grasshopper, Rhino) that is not always the case but for the sake of simplicity Dynamo prefers this solution.

Good luck!

#5

thanks very helpful and synthetic line.bybestfittroughpoints the command, and if the surface had been curve exists a similar command? to create curves and no polylines. in general, I’m having some in general I am having some difficulty in identifying the controls, you can advise the best way to learn Dynamo? I started reading a manual based pyton.

#6

I learned by first getting some basic intro from folks at ModeLab and then by just playing around with it. I tried to use it on a project for some basic tasks first then increased the complexity as i was getting more familiar with it. I hear that Dynamo has a great series of tutorials that ship with it. I still use the forum, GitHub and word of mouth to ask for help with things that I dont know. You can check out my blog at www.archi-lab.net for some free tutorials and downloadable content. In general I would say, come up with a task, try it, ask here for help, get it done, then do it again. Sooner or later you will be pretty darn good at it. Trust me. Oh and Twitter is great. There are folks like Andreas out there that are great Dynamo resources and always willing to help. My handle is @arch_laboratory, feel free to ask there for help too.