[deg2]

I don't have a 3D program, all my work is in 2D. Recently received a small dfx part file that was in need of some adjustment. Contained in this file were some 3D Polylines. I've tried saving it to R12 dfx (have used that successfully before to break down splines and ellipses)...That didn't work. Still a 3D PL.

I exploded the PL's and examined all the Z coordinates....all read 0.

I guess my question is, do I have to concern myself with the 3D P-lines (Z=0) or will they confuse a laser cutter? And, further, if by chance, there happens to be a Z coordinate in there not = 0, would that mess up a laser cutter?

Don

[Jorge-D-Fuentes]

Not sure if this may help you, but there's a chance the plane you're working on isn't the 'top' plane.
I've worked with a few 3D files with some lines that I use for the LASER, and when they're exported using the Front/Side/Perspective plane as their base instead of their TOP, the LASER won't recognize the dxf as having usable lines.

I'm not sure if this information is helpful, but it couldn't hurt to check.

[deg2]

Not sure if this may help you, but there's a chance the plane you're working on isn't the 'top' plane.
I've worked with a few 3D files with some lines that I use for the LASER, and when they're exported using the Front/Side/Perspective plane as their base instead of their TOP, the LASER won't recognize the dxf as having usable lines.

I'm not sure if this information is helpful, but it couldn't hurt to check.

G'morning Jorge,

Thanks for the reply. I don't know how the file was saved originally. As I said, I work only on a 2D platform and received them from a third party. I've attached a small .dxf or one of the parts. I think the easiest way for me to handle this is just to send this file to one of the cutters and see if they can read it correctly. But, I would really like to understand what's going on here and how to handle these 3D lines in the future...Thanks again for your reply...

[Jorge-D-Fuentes]

I went and loaded the SHADOW TEST.dxf that you attached.
I don't see any 3D polylines that would cause a problem (everything looks 2D and, as you pointed out, all z coordinates are set to 0)

As for your question regarding if it will 'confuse the LASER'...

I'm not sure about your LASER cutter, but on my LASER engraver, any lines that are in 3D space cause a problem ONLY if you are attempting to hatch-blast the area within their perimeter. However, when using the lines as a toolpath for an outline, the LASER just ignores the Z coordinate and essentially is 'projecting' the linework on to 2D flat space.

I imagine your LASER would behave similarly. But you're right; the only way to know is to try it out.

[deg2]

Hi Jorge,

I'm not sure why it happened but I downloaded the file and you are correct. In the dl'd file there were no 3D Plines. I suspect it's something the site upload did to break them down. The original file had 3D Plines for all the curved lines....mystery of the internet....

As I don't, as of yet, own a laser, I contacted one of the vendors that I have my cutting done by and his program didn't read those lines until he exploded them in Acad. He did however point out that the number of Plines was enormous and would take a great amount of time cutting them. With that in mind, and knowing that I really didn't need that much accuracy, I just traced the parts (only had 10 to do) as 2D Plines with fewer segments.....vertices went from ~1500 down to ~100...big time saver and enough accuracy for the job at hand.

I do appreciate your follow up. And I did learn quite a bit from this exchange...Thank You Very Much,

Have a great weekend,

Don

I went and loaded the SHADOW TEST.dxf that you attached.
I don't see any 3D polylines that would cause a problem (everything looks 2D and, as you pointed out, all z coordinates are set to 0)

As for your question regarding if it will 'confuse the LASER'...

I'm not sure about your LASER cutter, but on my LASER engraver, any lines that are in 3D space cause a problem ONLY if you are attempting to hatch-blast the area within their perimeter. However, when using the lines as a toolpath for an outline, the LASER just ignores the Z coordinate and essentially is 'projecting' the linework on to 2D flat space.

I imagine your LASER would behave similarly. But you're right; the only way to know is to try it out.

[Jorge-D-Fuentes]

Glad you got some knowledge out of this.

It's likely that the conversion program, whatever that may be, took the simple splines, and converted them into many many polylines. I've had this happen when having to deal with conversions.

Some CAD programs will create a bezier curve, or a spline, or an arc, with beautiful control points, etc. but then when you export the file to DXF, there will be a set of toggles, checkboxes, and options in a dialog box. If you choose something that ends up "approximating curves as polylines", you will end up with a huge file size and many many small polylines.