Spiral from point to point with non constant slope

Hi guys,

I know how to make a spiral using polar component. But what I am trying to make is to have

  1. Two points which I can move on a circle and these point will always be an end of spiral curve
  2. And spiral between these two points should have variable slope.

For second question I thought to use graph mapper

Hope images will help
CustomSpiral.gh (6.4 KB)

I’m not a Graph Mapper specialist but it can be used to do what you want.

In my case I used a python script to generate the spiral. I needed to divide the resulting curve and deconstruct the points to get the Z values of the points.

CustomSpiral.gh (20.8 KB)

1 Like

Here is a similar method to Martin, but without creating the initial spiral:

CustomSpiral_V2.gh (10.6 KB)

1 Like

Thank you guys,
@Adam_M I did something similar to yours but,

Not sure how to keep track of the angle between two points?
You see when I past 180 degrees it doesn’t work ?

CustomSpiral.gh (16.4 KB)

Basically how to fix this ? :slight_smile:

1 Like

CustomSpiral.gh (15.8 KB)

1 Like

Hi @Mahdiyar

Thank you. I made a wee progress on this.
I am trying to build a second spiral on top of the first one.
I was using the same principle but for some reason it is still misses the point (picture 1)

In the middle I do want the spiral to change its direction. (picture 2 is correct)

CustomSpiral_01.gh (26.1 KB)

1 Like

Like this?
CustomSpiral_01_v1.gh (30.6 KB)

1 Like

Thank you @Adam_M
I solved it last night :slight_smile:

Hey Adam,
I still struggle to get the spiral look the way I want. Basically what ever I do two spiral curve are parallel :frowning:
I want to be able to control the amount of squashiness , see image below… red line it is what I want

CustomSpiral_03.gh (37.0 KB)

I’m not sure exactly what you are looking for, but maybe this could give you some ideas:

CustomSpiral_03_v2.gh (37.3 KB)


Thank you,
Will take a look over weekend.
Have a good weekend Adam, thanks for help

Well not exactly :slight_smile:
Two spiral curves have to start and end in opposite points :slight_smile:

@Adam_M , I thought about it and it looks like, I need

  1. Two spiral curves which start fro opposite points , this is done
  2. One of the curve has control of pitch or squishiness without actually increasing number of revolutions of the spiral.

So when I loft / rail between two curves profile appears squished at one side.

Hope my sketch will help.

Hi guys @Adam_M @martinsiegrist @Mahdiyar
Apologies for asking to many questions.
I made an experiment in rhino, to be able to get the shape I want I had to use mesh cage to deform curves.
Is there a way I can do the same with graph mapper or scale within Grasshopper ?

CustomSpiral.gh (24.0 KB)

1 Like

Thank you @martinsiegrist
I will take a look now.
I was trying to do it with attracting points… to be able to have more control.
Not sure how to fix the curve at ground floor though :slight_smile:

It is difficult to help you without a file.

Sorry @martinsiegrist
See attached CustomSpiral_03.gh (55.1 KB)

I placed only one point for now, but I assume I can use multiple attraction points to control the curve. Almost the same way you did with graph mapper

Sorry can’t see the point because it’s not internalized.