# Managing planes - 3d arc

Hello everybody.
Here i have this line, and i got a point on it. the goal is showing the rotation of the point on the plane, with an arc.
I wanted to find the direction normal to the curve, to use as the tangent of the arc using the planes, but I couldn’t and thought of another strategy, like this.
i drew the points and the arc on rhino, preemptively. then i used the points to build the arc with grasshopper

studio-show rotation with arc.gh (10.4 KB)

Anybody with any suggestions how this could be done using ‘perp frame’ 'align plane` or 'adjust plane` ? I didn’t quite understand how to use those commands

Regards
Ascanio

i’m sorry, that’s not not exactly what i meant. I’ll post you an other definition that does what i want with all parametrized

@HS_Kim

take a look here
studio-show rotation with arc.1.gh (15.0 KB)

i just want to re-orientate those planes to get the blue normals and get the arc but i can’t figure out how to do it.

1 Like

@HS_Kim
thank you for your time, this solution is nice but doesnt work in all cases for what i need.
I woul like the arc is always an arc of a circle.
let me try to explain. i want the arcs to describe the rotation of the point, so they must always be arcs of circumference.

I drew the arcs i want in rhino to try explain better what i mean.

This solution works when the angle of rotation is 90° like here, and coould be ok.

but the angle isnt always 90°. Let’s suppose i have different angles. For example:
angle< 90°

angle> 90°

Because obviously when you change the angle, the tangent you get in this way is different.

anyway in particular i would like to solve the problem using in some way the commands align plane/ adjust plane, is it possible?

I found a solution quick and dirty way to solve. however, any advice from you is welcome

using rotate 2 times, once to find the end point of the arc (variable) and once to find the direction of the tangent normal (fixed)
studio-show rotation with arc.2.gh (17.9 KB)

result with same angles of above:

regards

Check this as well.

studio-show rotation with arc.1_reV2.gh (13.8 KB)

2 Likes

very cool this one. i needed a bit of time to understand.
I ask you a question, starting from this definition I derived this.

now I’ll create a new topic.