# Create surface from Polyline point **URL:** \ **Category:** Civil 3D\ **Tags:** dynamo\ **Created:** [October 10, 2024, 7:20am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042 "2024-10-10T07:20:05Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![shirai-a](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@shirai-a](https://forum.dynamobim.com/u/shirai-a)\ **Post date:** [October 10, 2024, 7:20am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/1 "2024-10-10T07:20:05Z")
Hello I am wondering how to select a polyline and create a surface from the points on the polyline. I tried the method in the image but it didn’t work. If I could do this, it would be useful for creating a simple layer boundary from several layer cross sections. ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/1/b/1beeded5ff272619c3e3bed25910dc78ad8774d7.png) ---
**Author:** ![jacob.small](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/jacob.small/32/161030_2.png) [@jacob.small](https://forum.dynamobim.com/u/jacob.small)\ **Post date:** [October 10, 2024, 7:54am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/2 "2024-10-10T07:54:26Z")
Polycurve.Points might exist in your Dynamo version. Using that into Surface.ByPerimeterPoints should make short work of this. If that node doesn’t exist as you’re on an older build, pull the start point of each curve segment as you are. Since your polycurve is closed (you can not make a surface otherwise) the end points are all duplicated by the subsequent start point. ---
**Author:** ![ddrennen2QDK2](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@ddrennen2QDK2](https://forum.dynamobim.com/u/ddrennen2QDK2)\ **Post date:** [October 10, 2024, 4:05pm UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/3 "2024-10-10T16:05:52Z")
you need to work backwards from this node… ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/9/3/9342d00164f593084f6bd5c60ee643bcbe9343a8.png) ---
**Author:** ![ddrennen2QDK2](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@ddrennen2QDK2](https://forum.dynamobim.com/u/ddrennen2QDK2)\ **Post date:** [October 10, 2024, 4:11pm UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/4 "2024-10-10T16:11:12Z")
[Tin Surface - Create From Polyline (Selection).dyn](https://forum.dynamobim.com/uploads/short-url/n9FFtwGAvlgJMvvkfv7SHazmhwI.dyn) (23.9 KB) try this… ---
**Author:** ![shirai-a](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@shirai-a](https://forum.dynamobim.com/u/shirai-a)\ **Post date:** [October 17, 2024, 8:52am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/5 "2024-10-17T08:52:05Z")
Thank you. I tried it, but I got the following error message. List First Item operation failed. Index out of range. Must be non-negative and less than the size of the collection. Parameter name: index – Listflatten operation failed. Object reference not set to an object instance. Do you have any idea how to solve the problem? ---
**Author:** ![shirai-a](https://avatars.discourse-cdn.com/v4/letter/s/e47c2d/32.png) [@shirai-a](https://forum.dynamobim.com/u/shirai-a)\ **Post date:** [October 17, 2024, 8:53am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/6 "2024-10-17T08:53:17Z")
![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/9/1/9178b3e07e70aa01f1143fd960691fe8bc5cdfb7.png) ---
**Author:** ![ddrennen2QDK2](https://avatars.discourse-cdn.com/v4/letter/d/e47c2d/32.png) [@ddrennen2QDK2](https://forum.dynamobim.com/u/ddrennen2QDK2)\ **Post date:** [October 17, 2024, 9:47am UTC](https://forum.dynamobim.com/t/create-surface-from-polyline-point/105042/7 "2024-10-17T09:47:42Z")
If you post your .dwg I can take a look. I think you don’t have a cogo point group in your drawing. If that doesn’t work…. You must be using the most current version of C3D and dynamo. That too could be the problem. Which version of C3D dynamo are you using ?