Lines normal to curves directonal issues

After 3 days of trials and errors I decided to throw my towel and ask for help.

My problem is (I think) simple to understand and, as far as I have read from the posts, quite common as it is related to the way GH defines a plane on a planar curve.

Here it is:

I have a number of curves extracted by intersecting a surface with a plane.

I would like to draw lines at equal intervals normal to these curves.

The problem is that since these curves are a combination of convex and concave the direction of the curves normal to it is difficult to control. as you can see from the files the planes x & y axis is rotated 180deg.

I believe is a similar issue related to Offset Curves.

Here attached are the base files and relative screenshot.

Thanks in advance to your help.

Attachments:

Replies to This Discussion

Permalink Reply by peter fotiadis on June 12, 2015 at 5:43am

Hmm ... controlling "zero-twisted" (in relation to what , may you ask) coordinate systems (planes, that is) is not that easy.

Notify if you want a solution (in C#, no components of any kind) that does this. For instance imagine that you want to align planes "along" a helix in order to do that "ramp" (sweep1 + on "ramp" rail + correctly oriented profiles):

the lime yellow ones is what GH can do, the others is what code can do.

Permalink Reply by Roberto on June 13, 2015 at 2:58am

Dear Peter,

thanks for your reply.

I am not sure mine is a "twist" problem.

I would like the planes on the lines to have the x and y oriented uniformly, if you know what I mean.

At the moment only 2 out of three share the same orientation. The 3rd flipped!

Permalink Reply by peter fotiadis on June 13, 2015 at 4:21am

Dear Roberto,

I've used the term "twist" to describe a general "dis-orientation" from what is ideally intended (may differentiate according the goal, I admit).

Thus "twist" can have a variety of meanings. Try to deploy planes (and orient a test profile for sweep1) in a helix like the above to get the gist of my meaning.

In any case and if you can't find/figure another solution ... notify: I could prepare an over-simplified C# version for you ... but still that would be 100% terra-firma if you are not familiar with that kind of things (it looks and behaves like a "component" or a "cluster" or an "add-on" thingy, mind).

Permalink Reply by Roberto on June 14, 2015 at 8:27pm

Dear Peter,

I am familiar with a C# component in terms of how integrate it the workflow etc.

I would be curious to see how you would tackle the challenge. Would it require lots of work from your side?

Permalink Reply by peter fotiadis on June 14, 2015 at 11:59pm

Work? not at all since they (I have several) are made long time ago.

I'll post soon 2 C# that could allow you to handle a variety of cases with regard "alignment" issues.

Permalink Reply by peter fotiadis on June 15, 2015 at 3:01am

OK, get these 2: the simple is where to start (the other is ... er ... "less" simple, he he).

In general we could "orient" (should I use the term: "constrain"?) coordinate systems (via code) with every imaginable way (even a chaotic one, he he).

Purpose of the simple C# is to create suitable coordinate systems mostly for AEC related things [added the primitive ramp example] and the likes, but I could easily modified it to suit your specific requirements (since "orient" [ or "twist"] has many interpretations, he he).

Play with the DoYouFeelLucky boolean (i.e. GH way VS the Lord).

Note: Clint E uses this C# as well for reasons that he hasn't explain clearly to me.

best

Attachments:

planesVSus5_DEMO.gh, 362 KB
planesVSus5_Simple_Demo.gh, 334 KB

Permalink Reply by Roberto on June 15, 2015 at 7:21pm

Peter and Pieter,

I would like to thank you both for your help....

It appears that Nikos gave me the solution I was looking for...I will test it today and see if its stable enough for my set of designs..

Thanks again to all of you.

Permalink Reply by nikos tzar on June 13, 2015 at 4:28am

Hello Roberto,

your .3dm.rhl file is not recognized from rhino as a valid file. Could you re-upload?

Until then, please check this discussion, as it sounds like you have a similar problem.

Permalink Reply by Roberto on June 14, 2015 at 8:32pm

Nikos,

here attached is the re-uploaded file for your use. I am also including a version 4 just in case. Please let me know if you still have problems opening it.

Thanks for your help.

In the meantime I will have a look at the discussion that you shared with me.

Attachments:

curvesOffsetDirection_V4.3dm, 161 KB
curvesOffsetDirection.3dm, 162 KB

Permalink Reply by Roberto on June 14, 2015 at 9:59pm

Nikos,
I have studied your definition from the discussion that you have recommended. Thanks for sharing that...
Here attached is my attempt to integrated into mine (unfortunately is still not working). As you can see half the planes on one of the 3 curves are flipping.
Any idea how to fix that?
Thanks in advance

Attachments:

curvesOffsetDirection_01.gh, 9 KB

Permalink Reply by Pieter Segeren on June 15, 2015 at 3:16am

Hi Roberto, if you use some other vector (than Z-unit vector) to align the frames, for instance world X- or Y-vector (or something in between), it will work.
(May I suggest using the PerpFrames component instead of DivideCurve + PerpFrame, it's a little more concise)

Permalink Reply by nikos tzar on June 15, 2015 at 4:13am

Hi Pieter,

I just saw your post.

I believe what Roberto wants is to have the perpframes as they are created, but with their X axis always pointing on the same side of the surface we would get if we lofted the curves...

I'd be curious to see if this could be achieved in a better way...