# Drawing an arc by three reference points **URL:** \ **Category:** Revit\ **Created:** [May 9, 2018, 10:55am UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769 "2018-05-09T10:55:08Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![alex23](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@alex23](https://forum.dynamobim.com/u/alex23)\ **Post date:** [May 9, 2018, 10:55am UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/1 "2018-05-09T10:55:08Z")
Hello, I am trying to create an arc that passes by three reference points in order to use it in an adaptive family. I know that with dynamo there is the possibility to draw a curve by reference points but actually it generates a spline while I need an arc that behaves exactly like that curve, keeping the reference points attached to the arc in order to manipulate it. Is there any way to do it maybe using also some piece of a python code? I will also attach a basic exaple in order to make myself clear. ![arc%20by%20reference%20points](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/e/7/e74639b85b1493b9d12ea993dbcf1320601e7940.GIF) Basically I need to find a way to model that curve in order to be an arc. Thank you! ---
**Author:** ![robert12546358](https://avatars.discourse-cdn.com/v4/letter/r/c5a1d2/32.png) [@robert12546358](https://forum.dynamobim.com/u/robert12546358)\ **Post date:** [May 9, 2018, 11:34am UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/2 "2018-05-09T11:34:39Z")
Can you Try this node **Arc.ByBestFitThroughPoints**?? ---
**Author:** ![alex23](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@alex23](https://forum.dynamobim.com/u/alex23)\ **Post date:** [May 9, 2018, 12:06pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/3 "2018-05-09T12:06:30Z")
Thank you for your suggestion, but unfortunately this node doesn’t accept as input reference points. My goal is to connect the reference points by an arc in order to use those reference points in a next phase to change the geometry of the arc. ---
**Author:** ![robert12546358](https://avatars.discourse-cdn.com/v4/letter/r/c5a1d2/32.png) [@robert12546358](https://forum.dynamobim.com/u/robert12546358)\ **Post date:** [May 9, 2018, 12:13pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/4 "2018-05-09T12:13:25Z")
I have connect four point and final output is curve. is any helpful for you?? ![34](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/4/3/43cb651d2dfa4ba8584bd272877ca19d381e10bc.JPG) ---
**Author:** ![alex23](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@alex23](https://forum.dynamobim.com/u/alex23)\ **Post date:** [May 9, 2018, 12:17pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/5 "2018-05-09T12:17:56Z")
No, I’m sorry, my problem is more complex than this. I need to use Reference Points to create my arc and not simply Points. ---
**Author:** ![Nick\_Boyts](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/nick_boyts/32/76313_2.png) [@Nick\_Boyts](https://forum.dynamobim.com/u/Nick_Boyts)\ **Post date:** [May 9, 2018, 1:35pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/6 "2018-05-09T13:35:57Z")
> [@alex23](#): > > I need to use Reference Points to create my arc and not simply Points. You can go back and forth between the two. Are you meaning _adaptive points_ rather than reference points? Why do they need to be reference points? ---
**Author:** ![alex23](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@alex23](https://forum.dynamobim.com/u/alex23)\ **Post date:** [May 9, 2018, 1:40pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/7 "2018-05-09T13:40:25Z")
I need them to be reference points because they will be hosted on other points connected to adaptive points to be used in an adaptive family. ---
**Author:** ![Nick\_Boyts](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/nick_boyts/32/76313_2.png) [@Nick\_Boyts](https://forum.dynamobim.com/u/Nick_Boyts)\ **Post date:** [May 9, 2018, 1:43pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/8 "2018-05-09T13:43:53Z")
But if this is all driven by Dynamo it doesn’t really matter which geometry you’re controlling. You can go back and forth like I mentioned by converting the geometry. As long as your adaptive points are in the right location everything should be good. ---
**Author:** ![alex23](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@alex23](https://forum.dynamobim.com/u/alex23)\ **Post date:** [May 9, 2018, 1:58pm UTC](https://forum.dynamobim.com/t/drawing-an-arc-by-three-reference-points/21769/9 "2018-05-09T13:58:40Z")
I think that what I am trying to achieve is exactly what was asked in this post: > [@Reference point driven arc model line using Dynamo](https://forum.dynamobim.com/t/reference-point-driven-arc-model-line-using-dynamo/14981): > > Is there a node (built-in or package) or any other way, to create a Start-End-Radius Arc model line? To clarify I trying to create a reference point driven arc using dynamo to connect the reference points. Thanks! In the end they don’t seem to find a solution neither.