How to 'crop' a g-code

[paulus.v]

Hi all,

I'm trying to figure out a way of cropping a g-code. There are only G1 lines, lot of them, and I need to eliminate the lines that are falling out of a given shape in the XY plane. I do not care about safeZ for the returning or any fancy features, just eliminating the unnecessary movement outside of the workpiece.
Generating a separate toolpath for each shape is time consuming... Not to be fooled by the simple appearance of the example, there is a lot of Z movement as well.

Any help is greatly appreciated!

Paul

[magicniner]

Generating a separate toolpath for each shape is time consuming

It shouldn't be, that is a really quick job in any competent CAM system, just use a tool path which supports a boundary or border to limit the cut area then add a boundary of the shape you need and POST the code for each shape,

- Nick

[paulus.v]

if you remember, here is why it is so time consuming... Now I have to generate separate toolpath for each triangle separately. I already have the toolpath for a surface big enough to include every shape I need, but now I need to eliminate the unnecessary movement.

[magicniner]

Yes, I guessed that it was related but generating the toolpath for a full surface then chopping up that toolpath simply isn't done, you chop up the surface then generate toolpaths for the parts or you cut the full surface then chop out the parts.
If your CAD/CAM isn't capable of the above you might need to cut two or more copies of your full surface to be able to machine out your parts

I don't think you realise just how complex a mathematical problem what you're asking for constitutes, it would need to

1 Recognise which paths needed to be truncated and where
and
2 Calculate which truncated paths then need linking
and
3 Would need access to the surface data in order to know how to link them without gouging your part
and
4 Generate the paths to link paths
and
5 Insert the links into the modified truncated code

The reason no one writes software to edit complex 3D toolpaths generated in another package within a boundary like this is because if they can do that they can write a CAM package that does the job properly in the first case and sell that to a mass market.

Simply buy a CAM package that can do what you need, or provide enough information about what you're trying to achieve so the guys can analyse the full problem, not just the problem as you see it after reaching your own dead end.

[paulus.v]

I don't think you realise just how complex a mathematical problem what you're asking for constitutes, it would need to

I do not see where it is the complexity. My g-code is a list of points defined by XYZ. I need to look at the the XY coord. of every line and compare with my shape. If the point is inside the shape keep the line, if it is outside delete it. That simple.

To get an idea of what I'm doing, I have the shapes already cutout and I'm applying a surface texture on them. I need to eliminate the extra movement, cutting out air, around the shape.

[magicniner]

I do not see where it is the complexity. My g-code is a list of points defined by XYZ. I need to look at the the XY coord. of every line and compare with my shape. If the point is inside the shape keep the line, if it is outside delete it. That simple.

To get an idea of what I'm doing, I have the shapes already cutout and I'm applying a surface texture on them. I need to eliminate the extra movement, cutting out air, around the shape.

Which leaves you with a set of moves which don't join up and aren't linked ;-)