Yes, exactly, but that is very different to scanning an object like your first post.
Perhaps more relevant to users like Gene is how I do most of my day to day CAM ... I use "Cut2D" from vectric ... I will make a simple drawing using lines, circles, rectangles to describe the part ... its just in 2D, .. I then add toolpath "drill these circles with 6mm drill, 20mm deep" .. "this rectangle needs to be a pocket 10mm deep, 3 passes, cut in a raster pattern with a finishing pass" ... etc, I can easily add in "bridges" to hold parts in place, preview the toolpath and when ready, get a set of gcode automatically. I can edit the drawing and recalculate the toolpaths at any time. Gene does it his way, it obviously works for him, I find drawing the design features first and then letting the software deal with the "how to create a pocket toolpath to match the shape" etc ... providing the drawing defines th features accurately, I getthe right result every time, without even seeing the gcode. It's a lot less complex than 3D CAD but for many machining operations it produces a perfectly adequate result. On Sat, 10 Oct 2026 at 18:54, Chris Albertson <[email protected]> wrote: > > > > On Oct 10, 2026, at 6:12 AM, maurice e heskett <[email protected]> > wrote: > > > > On 10/10/26 07:42, Robin Szemeti via Emc-users wrote: > >>>> Think of it this way: You are Michelangelo carving a statue of > David > > > OK, let’s make the example more relevant to CAD. Let’s say you are an > architect, not a machinist. Architects are also big CAD users. But no > architect would ever, even once in his life, use G-code or OpenSCAD to > design a shopping mall. > > So, a simple use of 3dCAD that shows parameters. The designer thinks a > fake column along a wall might look nice. So he draws a circle on his > screen and then a vertical line to cut it in half. Next, he erases half > the circle and ends up with the letter “D”. Next, he specifies a > dimension of 24 inches for the flat side. Then, finally, he places > the “D” on the floor and pulls it up to make a “half column.” Then he > sticks it on a wall. Then he duplicates the half column 50 times along > the walls. > > Finally, he asks the software to make a photo of the building for his > client. The client says “columns are too small.” > > Finally, the parametric part: The architect sees all of the columns > “depend” on the first one (because they are all copies) and the first > column depends on the letter “D” drawing he made. He sees that the “D” > is 24 inches across. He changes the 24 to 36. Next, the software changes > every column to be 36 inches wide. You can say that each of those 50 > columns “depends on a parent dimension.” > > Next, the client says “I like the size, but I’ve always liked those > classical-looking fluted columns.” So the architect changes the “D” to no > longer have a smooth arc and makes a more complex shape and saves it. As > soon as that sketch is saved, every column in the project updates to the > more complex shape. > > Of course, it is more complicated; the columns were not just made at some > random height; the designer said to pull them to the ”wall height.” And > then when he changes “wall height,” everything that depends on that > changes: the roof moves up, the volume of concrete needed changes, and so > on. > > > It is surprising how few dimensions one uses when building with CAD. > Think of a house. Where do the ceiling joists go? You’d be place each > one “8 feet above the floor,” because then when the client says he wants a > 100-inch ceiling, you would have to move 300 ceiling joists. SO, the > smarter architect says, “The ceiling joist goes on top of the wall and > makes direct contact with it.” Now when the wall height changes, > everything on top of it moves. How long are the wall studs? Ceiling > height minus the top and bottom rails. You use fewer numbers than you’d > think. > > > > > > > > > > > >> from a rock. There is no text file, only rock. Then 500 years later > >> someone uses a laser to digitize the statue. This is how 3D CAD > works: > >> you make an object, then maybe you need an STL file so you can print it; > >> the software uses lasers or whatever to measure the object and make an > STL > >> file. > >> > >> This is entirely incorrect, this is exactly how 3D CAD does not work ... > >> what you are describing here is nothing more than a capture of an > object, > >> an uneditable rendering. > >> > >> 3D CAD captures the design intent, a series of decisions and > dependencies, > >> and from those decisions and dependencies it creates the object. A > much > >> better way of thinking of 3D CAD is: > >> > >> You are Michelangelo carving a statue of David from a rock. You have > >> kept a detailed notebook of sketches, instructions, notes about the the > >> relative measurements of the statue, the angles of the arms and legs, > the > >> details of how the skin surfaces are smoothed from the limb joints etc, > >> everything you need to create exactly the finished work again from > another > >> lump of rock, even if the orginial is lost and no one even has an image > of > >> what it looked like. Essentially there is no rock, only the notebook, > the > >> text file. > >> > >> 500 years later, someone can perform the same task, but they can alter > any > >> of the design decisions or angles, or parameters used to smooth skin. > >> > >> The crucial thing to remember is the CAD file usually does not store the > >> object at all, it stores the set of instructions (th source code if you > >> like) to create the object when that set of instructions is fed into a > >> suitable tool that can interpret them (run the code) and build the > object > >> from scratch. > > That sounds like you are agreeing with me. Thank you. > >> > >> On Sat, 10 Oct 2026 at 04:26, maurice e heskett <[email protected]> > >> wrote: > >> > >>> On 10/9/26 18:02, andy pugh wrote: > >>>> On Fri, 9 Oct 2026 at 22:25, Chris Albertson < > [email protected]> > >>> wrote: > >>>>> Next problem is the FreecAD just happens to have the worst user > >>> interface of any 3D CAD system. It works, but the user experience is > >>> poorer than with other systems. > >>>> I have used worse, but it was a while ago. And I am prepared to > >>>> believe that there are worse out there. But that video seems to > >>>> suggest that it's improving fast. > >>>> > >>>> Arguably OpenSCAD is worse, depending on how you define "user > interface". > >>> Debatable. I like the text src I can see and edit in real time, but > find > >>> the editor a bit clunky. > >>>> But I am not necessarily disagreeing with your statement. I can't say > >>>> I am enjoying my ideologically-based switch from Fusion to FreeCAD. I > >>>> am not finding myself modelling for fun in quite the same way. > >>>> > >>>> But I _am_ confident that _my_ models remain _my_ models and will > >>>> always work with the version of FreeCAD on _my_ computer. > >>> The latter Exactly, Andy. > > Cheers, Gene. > >>> > >>> _______________________________________________ > >>> Emc-users mailing list > >>> [email protected] <mailto: > [email protected]> > >>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>> > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] <mailto:[email protected] > > > >> https://lists.sourceforge.net/lists/listinfo/emc-users > >> . > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] <mailto:[email protected]> > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
