Rhino points export to txt: Why is a series of points exported backwards?

Hi,

I am exporting a series of points and for whatever reason Rhino either records them backwards or exports them backwards when exporting points to a txt file.

For example: I can draw a horizontal line. Next, I can add points to the line one by one, from left to right. The issue is - upon exporting this series of points, they are listed from right to left.

Can anyone explain why Rhino does this?
Is there a setting that will allow me to record / export the points in the order that seems logical to my western-raised brain? (first, second, third, ect, - rather than third, second, first)?

I know I can write a simple script to fix this - but I want to understand what the logic is here, and what the other users and developers think about this detail, and whether it might be changed. (Or perhaps an option added to alter this function)

I’m drawing curves to create toolpaths for a cnc lathe and it’s important that the tool travels in a 1,2,3,4,5 direction, not a 5,4,3,2,1 direction.

Any help would be much appreciated.

If this isn’t something that will be fixed within Rhino I will plan on incorporating a bit of code to flip flop the numbers with the post processor program I am making.

I realize of course I could just add the points in a backwards fashion, but that can get confusing on more complex toolpaths. I have tried generating these toolpaths using Fusion360, but find their turning toolpath generation to be lacking / missing functions / not intuitive.

Thanks,

David

Hi David - unless you select the points one by one, Rhino just goes down the list of objects in the file, most recently added, or edited, are at the top of the list.

-Pascal

Thanks Pascal,

In that case I’ll plan on inverting the order in my post processor. Would be nice if there was an option to flip-flop that in the export settings as it’s not very intuitive for my project. I appreciate you explaining how that works.

Hi David - I don’t know which is simpler for you but you can add the reversing part in an export script. You can also order a jumbpled set of points ‘reasonably’ in space with a script.

-Pascal

Using cnc equipment- so creating an accurate path where I choose the points makes the most sense. I’ll plan on reversing all my toolpaths from here on. Thank you for the clarification.

Hi @David_Earle - here is a quick and dirty point order preview tool - it will reorder the points to match the preview. It could just as well export the points, but this is simpler for now.

PointOrderPreview.py (2.0 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"

That said the export order will still be reversed so you want this preview arrow to point ‘backwards’

-Pascal

Thanks Pascal! I’ll give it a try.

Daivd