G-code

Hello,

I am trying to create my own custom g-code writer for 3d printing, and I first have a basic question which I hope someone can help me with - I would like to split a list of points based on their z value. For example, I have contoured a shape at a desired height and I would like to separate each contour - is this possible? I was unsuccessful with the Sublist & Member Index commands. I have attached a sample definition. Any help would be appreciated.

Something like this...

G1 X81.78 Y-5.38 Z40
G1 X81.79 Y-5.61 Z40
G1 X81.51 Y-6.21 Z40
G1 X81.41 Y-6.55 Z40
G1 X81.43 Y-6.8 Z40
G1 X81.3 Y-7.1 Z40
G1 X81.3 Y-7.1 Z41.25

G1 X82.53 Y0.06 Z41
G1 X82.46 Y1.68 Z41
G1 X82.27 Y3.2 Z41
G1 X81.93 Y4.75 Z41
G1 X81.46 Y6.22 Z41
G1 X81.13 Y7.05 Z41
G1 X80.71 Y7.95 Z41

Attachments:

sublist_question.gh, 10 KB

Replies to This Discussion

Permalink Reply by Brian Harms on May 31, 2012 at 1:57pm

see attached

Attachments:

sublist_question_bharms.gh, 16 KB

Permalink Reply by Brian Harms on May 31, 2012 at 2:46pm

One way I like to compare items in a list without scripting is to generate a list of those items from index 0 to list length - 2 and index 1 to list length -1 (using series and list items).

Then you can compare those lists with equality, smaller, larger, or other components and use a member index to retrieve the indices where certain conditions are met. In this case i'm looking for the index when the z values of the points aren't equal. Those indices are used to generate sublists of the strings that were formatted. I'm not sure if the strings are exactly the way you want them but hopefully they are set up enough for you to tweak them.

good luck

Permalink Reply by Chris Hanley on May 31, 2012 at 7:07pm

I'm away from my machine but doesn't the contour command group by elevation already? I might try the shift paths component right after the contour component. One thing to checkight also be to verify all the contour curves are going in the same direction.

Permalink Reply by Brian Harms on May 31, 2012 at 10:57pm

Chris is right, I didn't even look at the right half of the definition - I just dealt with the points after they were flattened.

Here is a much shorter method using brep contour instead (so you only have to specify distance between contours. It doesn't create null values either).

For some reason the string formatting was a little weird - it would put the negative sign (-) in front of the string I added before each number. For example:

Format("{0:G1 X0.00 }{1:Y0.00 }{2:Z0.00}",x,y,z)

Is generating results like:

-G1 X23.56 -Y5.23 Z42.00

I'm not sure why these negative signs are where they are, but I used a replace string component as a quick fix.

Attachments:

sublist_question_bharms 2.gh, 6 KB

Permalink Reply by Brian Harms on May 31, 2012 at 11:30pm

I just realized the replace string didn't really work the way I set it up. This way does. Still just a quick fix, but does the job. I didn't set up a replace string for Z values (since they should never be negative as long as you start the contours at world XY.

See attached

Attachments:

sublist_question_bharms 3.gh, 6 KB

Permalink Reply by serifos on June 3, 2012 at 4:31pm

Thanks Brian...this works great!

Permalink Reply by Mateusz Zwierzycki on June 3, 2012 at 4:38pm

By measuring curvature at point and its neigbours (or angle between normal vectors) you can change interpolation and get G02 and G03

Permalink Reply by Thomas J. McLeish on May 9, 2019 at 1:53pm

For clarification, years later, I think you mean...

Format("G1 X{0:0.00} Y{1:0.00} Z{2:0.00}",x,y,z)

Permalink Reply by Ioan Festeu on January 30, 2020 at 10:41am

Thanks for the tip!

Permalink Reply by Adam Holloway on June 5, 2012 at 10:41pm

Hi Serifos,

I'm currently working on the same thing. What kind of printer are you writing the script for? Do you know of anyone else who has done something similar?

Permalink Reply by FrankS on June 6, 2012 at 6:45am