best method for creating a 2D p/line for NC routing from 3D solid?

[ZedEverett]

Well this is driving me bonkers.. :twisted: yes ,i have discovered a 3D polyline cant be joined to a 2D polyline and when i exploded 3Dpline then flattened it ,as recommended elsewhere on this forum,it seems its shrunk in length.The NC router I have access to has to use 2D polyline for the path of the cutter.I soooo wish i could simply fed the 3D object into the NC router software and that was all i had to do .Suggestions ,folks ?

[ZedEverett]

oops...forget to mention I am running 2011 AutoCad.I have tried exploding solid/pedit to convert spline to 3D polyline/flatten it,but this is no good it seems.

[ReMark]

Can you post a copy of the drawing wherein you have a 3Dpolyline and a 2Dpolyline that cannot be joined?

[Dadgad]

Well this is driving me bonkers.. :twisted: yes ,i have discovered a 3D polyline cant be joined to a 2D polyline and when i exploded 3Dpline then flattened it ,as recommended elsewhere on this forum,it seems its shrunk in length.The NC router I have access to has to use 2D polyline for the path of the cutter.I soooo wish i could simply fed the 3D object into the NC router software and that was all i had to do .Suggestions ,folks ?

When you say that it shrunk in length? Wouldn't that be a logical consequence of removing travel along the Z axis?
When measured from WORLD UCS it would appear to be the same length, although in actuality it would have been shortened, when measured in 3D.
I'm with ReMark, skeptical about your claim that it cannot be joined to the 2D polyline. Happy to try if you post it, or maybe just those 2 particular lines from your drawing.

[ReMark]

I'm not skeptical. I have 2013 installed. The Join command will connect a 3Dpolyline to a 2Dpolyline.

[Dadgad]

I'm not skeptical. I have 2013 installed. The Join command will connect a 3Dpolyline to a 2Dpolyline.

That was my position too, I find it hard to believe that it can't be done (skeptical, if you will of the OPs conclusion). Remembering that he is on 2011 I still feel that there must be a way, without availing ourselves of that new functionality in 2013.

[ReMark]

I think it best the OP try JDM's suggestion despite the fun we have had at his expense.

[Dadgad]

I think it best the OP try JDM's suggestion despite the fun we have had at his expense.

FIRE IN THE HOLE!

Hell, I still want a shot at joining them, but we haven't been able to coax or cajole a sample yet!
And yeah explode would probably be my first step right out of the gate.

[ReMark]

Since I was curious about this I conducted a simple test.

I drew a 2Dpolyline and a 3Dpolyline (separate layers/colors) then used the JOIN command on them. I checked the Properties of the combined line AFTER joining them. AutoCAD said I now had a polyline. It made no difference which one I picked first when I executed the JOIN command.

[Dadgad]

That would be using 2013 I imagine? On differing planes?

[ReMark]

Yes to 2013. No to different planes. Haven't tried that yet but I will.

OK. I'm baaaack!

Tested with a 3Dpolyine starting on one plane and moving to another the JOIN command does work and the result is a 3Dpolyline.

My 3Dpolyline showed a length of 75.9054 units before using the FLATTEN command on it. If I remove hidden lines the length drops to 64.0665 but if I don't remove them the length is reported as 63.9913 which strikes me as a bit strange.

[SLW210]

I am not a big fan of flatten for this reason. I prefer Sectionplane and the Sol commands to create 2d from 3D, occasionally I have acceptable results from Flatshot.

You could try downloading CadTools (http://www.glamsen.se/CadTools.htm) and using the Convert-3D polylines>Polylines.

[ZedEverett]

Ok.I went about the whole problem a different way.So many ways to 'skin a cat' in CAd isnt there? this is what I do now . 3D Solid>explode>delete surface meshes & geometry not necessary leaving only the bottom region of the solid>P EDIT to convert spline to polyline>BPOLY...and now I have a joined polyline HOPEFULLY that the NC router will like.

@SLW210 re:program that convert 3D polylines >polyline..........I had heard from a NC router tech that a particular program that I dont know the name of ,similar to what you describe ,generated hidden lines or ssomehing ,that created difficulties for the router .I may have that description wrong, but the crux of it is that it wasnt a good road to go down.Of course ,I am happy to be proven wrong n these issues.

[Dadgad]

Glad you figured out a way. :beer:
I apologize for having misread your first post, and becoming distracted by talk of 3D polylines.

I believe I have an easier way for you using SOLPROF.
In my experience SOLPROF is much more reliable than either FLATSHOT or FLATTEN.
I have no use for FLATSHOT whatsoever. I actually like FLATTEN, for simple stuff, but SOLPROF will handle much more complex shapes better.

SOLPROF > DELETE HIDDEN LINES > and yes to all of the other questions, use the defaults.
Go into modelspace and EXPLODE the block which will have been generated.
Select all these lines and change their layer to whichever you want.
PEDIT > ENTER MULTIPLE > JOIN > FUZZ DISTANCE 0.00 >

(I have never used BPOLY, just checked it out after reading your work around again, it may well be better than the PEDIT join I just endorsed.)

I think that may be easier for you, and yes, as you say so many ways to skin a virtual CAD-cat! :wink:

[ZedEverett]

I swear CAD is like a monkey sitting in a zoo.Every now and then it gets angry and throws poo at its operator.grrr!:roll: Now the BPOLY command is saying"a closed boundary cannot be determined".Now this puzzles me ,as the geometry i am tring to make a polyline boundary out of is the result of an exploded solid.Surely an exploded solid would have no gaps or it couldnt have been a solid?The BPOLY comand worked a treat on other solidss in the model that are identical as the one I am working on using the same BPOLY process ,so I am at a loss how it doesnt work..:x

[Dadgad]

My guess is that when deleting nonessential elements from the exploded 3D Solid you screwed up, or should I say erred.
Of course there is always SOLPROF. :whistle:

[ZedEverett]

nup.just discovered the problem.Whilst i ensured the offending 3D object ,prior to exploding,was 3D Aligned to a solid created in top view ,who would ve thought that when you explode said solid, and delete all the geometry you dont need, that the group of 3D polylines & lines ISNT aligned to the plane of the source 'top' object.I think I have just succeeded at throwing the poo back at the monkey..:D

iwill investigate SOLPROF to see how it goes .Thanks

[Dadgad]

Solprof will always do it relative to your UCS.

[ZedEverett]

SOLPROF.It distorts the profile.It seems when i try to align it to the original 3D object to check it out ,it clearly isnt the same shape.Very puzzling.I guess SOLPROF fools with Z axis .and i still had to re 3Dalign the SOLPROF model space object to my top view UCS 'source"3D object for the BPOLY command to work (the PEDIT join wouldnt work either ,no doubt for the same reason).Thanks for the info though as its always good to explore new approaches!


Solprof will always do it relative to your UCS.

[Dadgad]

I'm very surprised to hear that, sorry that didn't put you back on the tracks, Iwas pretty sure it would. :huh:

Thinking about this, what is your UCS?
It sounds to me like your UCS is not set correctly.
SOLPROF is meant to project your lines onto the XY plane in your viewport.
If in modelspace you look at the solprof blocks from left or right, you will see that they are not crooked.

Might the orientation of your model be an issue? It needs to be parallel to your UCS.
Are you able to post you r DWG here, or representative bits from it?

[ReMark]

Why don't you post a copy of your drawing so some of us here can take a look at it?

[ZedEverett]

Not really sure what you mean about correct setting of UCS? I created the model initially in top view . All the parts to be cut on the NC router have to be aligned to top view UCS thus the use of 3D Align.Havent explored posting .dwg files on here yet.



I'm very surprised to hear that, sorry that didn't put you back on the tracks, Iwas pretty sure it would. :huh:

Thinking about this, what is your UCS?
It sounds to me like your UCS is not set correctly.
SOLPROF is meant to project your lines onto the XY plane in your viewport.
If in modelspace you look at the solprof blocks from left or right, you will see that they are not crooked.

Might the orientation of your model be an issue? It needs to be parallel to your UCS.
Are you able to post you r DWG here, or representative bits from it?

[ZedEverett]

OK ,here is a part of my model I am making.Just checked the polyline that BPOLY creates against the original(the copy was exploded) and notice that it the polyline from BPOLY is slightly bigger than the original 3D object.WTF! I am only talking 0.06 and 0.006mm distance and the object is to be cut out of plywood ,so I am not too worried ,but never the less it puzzles me still.It seems the damn monkey is reloading for another barrage! LOL

[Dadgad]

Time constrained right this second, not really looked into this yet, but viewed from FRONT you can see this powder blue solid is not parallel to the XZ plane, as referenced against an XLINE.

[ZedEverett]

mmmm...i think i will be doing 3D Align command in my sleep.:roll: Thank for the input.

[ZedEverett]

Just had a breakthrough with BPOLY (boundary polyline command).Its been freezing my program and I usually have to use Task Mangler to close CAD.Grrrr. Someone on here mentioned that CAD has to calculate a lot of data when BPOLY command is happening, and as I had many 3D objects involving different layers, I decided to turn off all layers,while creating a new layer called BPOLY. The object i wanted to create the boundary polyline from, would be temporarily changed to BPOLY layer ,leaving all layers off. BPOLY works a treat after that ,counting of course its 3D aligned to an object created in TOP View UCS.

Sooo...my recommendations of generating closed polylines for NC routing from solids is ; orientate solid to TOP view UCS using 3D Align/explode twice/delete all unnecessary lines on the exploded 3D object other than the bottom or top geometry/PEDIT/multiple/'yes' to polyline creation & 10 value/create layer BPOLY/change layer of geometry to BPOLY layer/ qsave/turn off all other layers/BPOLY and the rest is plain sailing. I dont think I have forgotten anything,but let me know if there are any other suggestions.