Decompose Point location in user-defined plane?

Hello,

Is it possible to retrieve the x, y, and z values of a point in relation to a user-defined plane?

For example:

if I create a plane with user-defined x and y directions, and I have a point which moves back and forth across the x-axis of the plane, and I would like to retrieve the x-component of the point based on the plane's coordinates (not world coordinates) to see when it is positive or negative... can I do that?

Thanks,

-Brian

Replies to This Discussion

Permalink Reply by Aris Nikolopoulos on September 27, 2016 at 4:29am

this is an initial approach, but I'm sure there can be a foolproof protocol for the combination of various LCS's.

eg:

COMPUTATION:

numeric values are unaffected
points, curves, vectors are translated (either to world coordinates or to another LC system if they enter it).
resulting geometries occur through the combination of both
transformations are defined by the LCS within which they reside.

INTERFACE:

No overlapping of LCS's
LCS rectangle cannot become smaller than the area of its residing entities
LCS rectangles always push outside entities when resized.Possibly accross the entire axis of the resizing (similar to alt+dragging but also to the up/down direction)

in the example that you gave, lenght/area/volume (as numeric values) would exit the LCS unaffected. -they would only change if we took the box out of the LCS since it would be reconstructed according to the world system.

I have very limited programming skills so I cannot fully understand the challenges of implementing it but local coordinates is to me something pivotal in creating-and understanding- complex forms. Grasshopper from the first moment i started using it spoke my language and I love it!!! not being able to understand local coordinates is for me its only drawback and from what i understand from the forums a lot of people face this problem -even though many of them don't realize it-

If I could help in any way in creating a LCS please tell me!

Permalink Reply by Aris Nikolopoulos on September 27, 2016 at 5:09am

sorry if my last answer looks like it doesn't take into account what you said, i had already started editing and didn't see your answers.

here is an example i just made in sketchup. this 'magic' stair was created with 20 components. in each of them, it was very very intuitive to create a spiral in the local coordinates and then the transfomations were translated to the rest of the components with the transformations applied. now i know this can also be done in gh (and with much more control) but i find it more 'object oriented' to work with local coordinates.

Permalink Reply by Aris Nikolopoulos on September 27, 2016 at 5:17am

Permalink Reply by David Rutten on September 27, 2016 at 5:38am

As a quick note, I'm not complaining about it being difficult for me as a programmer. It probably will be, but it's my job and I'll just have to suck it up. What I'm worried about is transferring responsibility to plug-in developers. If it becomes really difficult to add a new geometric type to Grasshopper, then it will stifle plug-in development. That's my worry when I talk about programming difficulties.

I understand and agree with your conceptual approach. I think it is flexible, powerful and closely mirrors the logic of how change-of-basis transformations would be applied in sequence.

I'm very unconvinced regarding the interface though. Having the sizing of regions be limited by both their content and surrounding regions makes me itchy. I can't imagine that feels good. However I see other approaches here that may be less rigorous but more friendly.

My second big worry is the preview display. Do you draw preview geometry in world space (in which case what you see on the screen does not match the actual coordinates) or do you draw it in local space? Either way it can be very confusing to see different geometry at the same time reside in different spaces.

I do think Tom was right in asking for a real world example. It usually helps a lot to actually have a real problem which demands solving. Can you outline a case? And if you do, can you put it in a new discussion, this one is running out of reply space.

Permalink Reply by Brian Harms on November 29, 2011 at 9:44am