Laser Cut Cobblestone Streets and Paving

[NE Brownstone]

Thanks Dave,

Wow, OK, makes sense.  It's basically a laser printer with a bada$$ laser.  I wasn't sure if you could read nc, txt, dfx, etc.  The post processor for my router uses them, but I wasn't sure if it operated the same way.  I draw in autocad then save as a dxf, which the PP converts to  a text file.  I have a raster program that converts to .nc, but I have no idea what the actual difference might be.  They both look the same code wise in the code window of my control program.

Thanks for the info.

[Frederic Testard]

Dave, have you tried to read the eps file I "sent" you? No emergency but it's to see if this direction works.

[DaKra]

Hi Frederic, yes and I sent a PM reply.  Did you get it?  Please check and LMK.  One file worked, but would not let me edit everything, the other file worked as normal.   I think that was the .eps       

[Frederic Testard]

Thanks Dave. I usually receive emails to tell me there's a PM but apparently it didn't work thus my question.
It's easier to me to make eps files than pdf due to memory limitations of my converter so it's good you were able to work with the eps.

Now question to the group : is there an interest in this cobblestones? As Dave mentionned, the lasercutting of these is expensive because there's a lot of work, but cutting one and then replicating with a mold and plaster castings could be interesting. I'm not in business, nor do I model cobblestoned places, but I'd be glad to let one of the 'businessmen' here use the file I wrote for free. (Even if I still plan to add the 3D feather relief Dave suggested a few posts earlier).

[DaKra]

Russ I re-read your post (all those references to digital file types do my head in) just noticed the reference to CNC router.  Are you using one in your miniature work?  Hope you'll tell us more about that.   Anything miniature CNC is very interesting.   

Dave

[NE Brownstone]

Hi Dave,
Yes, as a matter of fact I do use it for some of my work, particularly brick.  I have a small table top router that I had to modify to hold a high speed dental hand piece, add a vacuum table and a dust collection system.  None of them being an option from the factory.  I messed around with doing brick by hand, but was not happy with it.  I just can't get over running into bricks while cutting vertical lines.  Not to mention creating different patterns.  I can now mill out any bond pattern (English, American, Flemish, rat-trap, etc.) for single plane brick walls in any scale. It's not a production machine and I use it strictly for tooling because it usually takes a few hours to engrave a brick pattern on a plaster slab.  It's not fast, but it beats the heck out of hand carving and I'll be making a mold from the piece anyways. 

Using the router is a bit tricky because I'm using hard tooling where the laser uses soft tooling.  Annoying things like tool lengths and offsets make it somewhat more cumbersome.  I don't have any real 3d programs, which I'm not sure if it would help anything anyways, so I have to think 3d in 2d and create 3d by depth of cut.  Plus, I don't have an auto tool changer and Mach3 doesn't support it and that makes it even more cumbersome.  Just think about having to mill out a fancy brick wall with detailed cornices, or eaves with modillion and machicolation patterns, then having to change tooling and the program just to engrave the brick mortar lines. It's more annoying than anything.    It's easier to make the parts separately then build up the wall pattern.  Needless to say, I just can't throw a blank sheet of plaster in there and let it rip.  I wish!   

I do have a photo milling raster program that I experimented with to see if it would work for random stone walls, but the end result still looks computer generated.  I would need to do some serious hand work to make them look acceptable. It does have possibilities for specific proto work, but it's still requires time consuming drawing manipulation. 

Fredrick,

I'd like to try out your cobble stone program if you don't mind.  I have seen .eps extension in the "save as" in one of my programs, so it may be able to work.

[Frederic Testard]

No problem if you want to use the cobble stone file. Do you wish me to do the 3d feathering as explained by Dave, or will you take it as is?

[NE Brownstone]

Hi Fredrick,

Let's try it as is. 

Russ

[Frederic Testard]

Russ, I've sent you a PM with the link to get the file.

[NE Brownstone]

Hey guys,

Sorry for the long wait.  I was able to download your file Frederic, but my programs kept converting it to a bit map.  It did work, but the resolution is rather lame.  I had to use my raster program.  Honestly, a high contrast B&W photo would have worked just as well except you'd have to take the photo from an airplane or high building.  These raster programs work rather well for carving out not-to-detailed photo lithophanes  (back lit photo carvings)which look detailed to the naked eye, but suck for our level of detail. Especially under the camera.

Yes, I could have dialed in the step-over, but the time to carve this piece was around 2 hrs plus.   So, for scale brick and cobblestone work
I'd be better off with line drawings.   


   

[Frederic Testard]

Indeed the close-up is not very attractive, Russ...
Dave or Russ, could you send me a very simple .eps file that works for your laser - and your drawing program - so as to check what postcript functions they read easily and guess why the file couldn't be read properly?

[Hector Bell]

How would you propose getting rid of the steppy, stripey finish?
Also, real cobbles are not that regular.  You need an element of irregularity with any architectural feature as they, unlike the computer stuff, are laid by real people.
This looks like that old stuff Preiser or Faller used to do in the 60s.

Martin

[Frederic Testard]

Sorry, Martin, next time I'll think twice before sending a computer generated pattern.
Dave, Russ, I might try to put a little randomness on my lines - after all, I have a phd in probability - if you wanted to show me the kind of eps file your laser cutter reads correctly.

[Hector Bell]

Frederic , I'm all for taking the drudgery out of a job if possible.  Please don't get me wrong there.
But the steppiness looks like a lot more work to clean up.  And the regularity needs a bit of interruption, though quite how you'd do that on a computer I don't know.
These very continental patterns of cobbling are admittedly fairly precise, if I remember my time in Bavaria, but look at an average British cobbled street and they're all over the place, something I think would test a computer's ability to randomise severely.  IF it can be done and with a smooth finish, you've got a winner.
Until then, an old patternmaker like me still has a chance of earning a crust!

Martin

[NE Brownstone]

Hi Martin,
This was only a test to see if I could read Frederic's eps file, which I wasn't really familiar with, or how it acted.  The first drawing I was playing with ended up being saved as a bitmap, so I used a raster program that I have that obviously didn't work as well as I'd have liked.  However, I am happy to say that I was able to get the eps file to work on another program and can now node edit. Like you said, there's a lot of hand work both on the computer and post milling.