Metal cutting - oxyfuel cutting, plasma cutting, machining, grinding, and other preparatory work.
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It's cool man, you go right ahead. I welcome the opportunity to learn from the knowledgeable on any subject. I just can't resist the opportunity to take the piss when it arises. It's a character flaw of mine. :)


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Coldman wrote:Meanwhile, back at the ranch...
...the ugly duckling's learned to dance...
Raymond
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Is Blender an open source version of cad? I just rebuilt my pc around an intel i7 6700 with 32 gig of ram and a evga 1070 ftw. (I game a bit.) Would that run it?
I have more questions than answers

Josh
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No. Not by a long shot. Blender is a 3D modeleng and rendering suite that statred life as a character animation program. It is open source. It has some curve functionality, however crude. It's definitely nothing like autocad but can import and export autocad files (and many others) through built in python scripts. It has a video sequence editor, node based compositing and texturing system, heavily integrated python scripting capability, worlds premier uv mesh unwrapping system, bullet physics simulation, game engine, camera and object tracking system, etc...
http://www.blender.org

Blender demo reels will give you a feel for it's capabilities:
https://www.blender.org/features/reels/
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Raymond
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Before we go anywhere.... I am just a really smart guy with computers and have a knack for figuring things out. I have never been trained in CAD. I use CAD for my 3D printing and I've worked with my friend at his motorcycle shop to come up with a way to cut custom gaskets using a basic scanner and CAD with his Gasket Cutter which is basically a vinyl cutter with a branding for gaskets and a flat table vs. a rolled catcher.

That said, the blatant difference I see with Blender and AutoCAD is making a radius line. In G-Code for the AutoCAD export to a printer, you get true radius lines vs. steps/coordinates since it's a special command. HP Plotters have the radius command (almost all plotters are built on HP's CAD commands) however I can't find a freeware CAD program that does this. That said, 3D printers don't even use true radi, they use steps/coordinates hence no true perfect circles. I also notice AutoCAD has better tools for navigation in relation to schematic building and overall design especially when it comes to using 2D schematics packages with/out annotations. Still, 3D dimensional shapes seem to be simpler to build in Blender than AutoCAD.
Beyond that, Blender is a perfect replacement for AutoCAD in many situations and I'm quite sure will get the job done on most CNC systems and CAD drafting. I even find it compliments AutoCAD in many ways.

P.S. your system is more than capable of running any 3D design/rendering software.
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And I see Rambo replied with some more relativity for you :)
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So autocad produces real, rather than segmented curves?
Does that make that much difference to a stepper motor or just the software that controls it?
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I think I may have to do some more research. It's been 10 years since I built my last CPU so I'm just getting back into it. But I understand a little about what you said about the rendering of the curves compared to cad.
I have more questions than answers

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AutoCAD can interpret ARC (G02 and G03) G-Code commands unlike every other CAD/3D design program out there. When you're working with vinyl and/or gasket cutters, ARC is very important since you're almost dealing with an x-acto knife. The reason is because it's not uncommon you need 2-3 passes for a 1/16 sheet of vinyl/gasket. If you want a perfect cut without having to bust out your x-acto knife, then this is the ticket. When you're working in CNC and metal you're going deeper than 1-2 cuts so it's even more useful especially since an X-acto will not clean that one up.

ARCs vs. steps/coordinates keeps your tool sharp otherwise you're fighting pixels. It sounds weird but if you know about digital vs. true photography this should make a bit more sense. Still for the non-photographer, imagine a grid, then imagine cutting an ARC along that grid. There is never a true constant angle between grid points but that's how coordinate cutting works since it uses points vs. angles. You also need less code because it is one command to create a 90 degree 1" arc with arcing between degrees vs about 90 coordinates and the linear steps between. This is why AutoCAD will always prevail in any CNC world but you can certainly get away without it if you don't do this for production and/or don't care about your cutting tools.

I think some of this logic may be incorporated with the DXF/DWF AutoCAD formats but in general most applications that "convert" to this format never use ARC commands. This is why Blender does great for odd shapes, box shapes, and everything that does not need a perfect logical ARC. That covers most of your designs however to CNC machining, you'll still find your ARCs are better than anything else when required.

Oh yeah, you also need something to convert your whatever exported format to G-Code. STL is pretty universal but regardless your program that runs your CNC must interpret logically whatever format you can export.

So I don't sound like an idiot here's a technical explanation of the G02 and G03 commands:

http://www.cnccookbook.com/CCCNCGCodeArcsG02G03.htm
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You can see the anatomy of beziers very well if you zoom in on them in Photoshop. Seems like someone clever would be able to tell the program to skip every inside corner so that it doesn't cut like this:
[attachment=0]icon-design-12-opt.png[/attachment]
[attachment=0]icon-design-12-opt.png[/attachment]
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I can imagine that would be taxing on a cutting tool.
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I can say Adobe products are not capable of this because I was using Illustrator CS6 which is 100% vector and can print directly to a plotter using HP proprietary G-Code. Adobe does interpret correct ARC paths but it will not export them no matter what format you use. I learned this the hard way and I think it resulted in the demise of the gasket cutter despite the fact it was already on it's last leg.

Adobe Illustrator resulted in a pixel cut every time because it does not interpret those ARC commands in it's plotter export even when using the HP drivers. This resulted in erratic cuts that were damn near on point for an arc but you could tell an ARC was not used. With a CNC mill, I can see you getting away with this since the force is greater and the material removed is much less than vinyl/gasket material. You also have a constant rotating cutting surface vs. a static blade. Still you'd never get that perfect ARC much like 3D printing software.

Think of it like stop and go in city driving vs. highway driving. You get better gas mileage and longevity of your engine on the highway using constant speeds. Coordinate cutting is like in-city driving so you're always at a persistent stop and go which any motor/engine does not cope well with over time. As Rambo said, this is taxing on your cutting tool.

The simple story is there is no freeware utility that will offer you the ARC commands that I know of but it's not the end of your machining hobby/career especially if you know how to write/edit proper G-Code ;)
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I worked in a sign shop several years back and the owner used illustrator with his plotter a lot. The only thing that he used more than illustrator was flexi sign.
He just exported extended post script files (.eps) and it was go-cat-go. I never saw that plotter hiccup. It just didn't care. Of course it was a $30,000 plotter/software package that he had on lease so that may have something to do with it.
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Another thought... Blender does great at axial and rotational validations. This means you can setup a part virtually to ensure they do not collide with others. From there the exported formats can go to AutoCAD formats so you can do your pre-checks and then export with AutoCAD. Considering the versatility of Blender, this is why it is complimentary to AutoCAD and a great starting platform. Still the 2D planar travel of your tool is very important to consider. If it's a rotary tool, life is good. If it's a static tool with one cutting plane, then life could suck.
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Rambo! We're both tearin up this thread :D

His Gasket Cutter never had issues for the longest time but it finally started not liking life so much. It was a 90s HP plotter with 15 years of service in the end despite the re-branding. It required more cutting force than vinyl due to material and thickness. So all was well in general but you could tell the performance difference between ARC cutting and coordinate cutting. The poor thing was already about to die and I had to repair several components but in the end it seemed like the linear cuts vs. ARCs were the final salts in the wound.

I'm curious about your buddy's exported format and/or printer drivers he used because who knows, maybe there's a useful difference when using the Adobe software suite.
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Hey Josh! Going around Thingiverse I find a lot of people use OpenSCAD and OpenSCAD just came out with Customizer which has really revolutionized CAD. I've seen it floating around for a few years now but it's really taken off the last three years in the user space. It's also Free!
I've done mostly modeling and things that work well for what Blender can do but I do believe I'm going to switch to this since pirating software doesn't always come with good benefits and can come with more headache than satisfaction, plus the occassional PC equivalent of VD.
I've seen some amazing projects and the documentation/drafting output it gives seems up to par with AutoCAD.

I've got some more stuff to design up soon so I might remember to post back here and tell you just how easy or PITA it is but in your research time, check it out!

I have used Libre CAD which is another very well known popular setup but I found it had limitations with exporting to G-Code and did not offer the arc commands. This may have changed in the last 4 years though.
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As I recall it was just .eps files he was exporting. I don't remember what type of plotter it was, only that he leased it from a company in alabama. He was supposed to be a graphics guru but i schooled his ass on many occasions. I remember telling him that i would prefer to create my vectors in photoshop and send them to illustrator for conversion to .eps. He told me that you can't do that because illustrator doesn't read photoshop vectors.
I told him
File > Export > Paths to Illustrator.
Some guru.
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We also have Adobe Bridge these days but yes Export is the easiest method :)

Back to AutoCAD pre-2k, OpenSCAD is definitely in the ballpark. Still it should fit the bill if you know coordinates and geometry. This is how true CAD is anyways so it's a worthy learning curve.
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