Posted by Michael Gilligan on 14/03/2015 13:29:21:
Posted by blowlamp on 14/03/2015 11:48:51:
… The difference is that the CAM system will output only straight line moves (G01) to represent an arc or circle if that is all it is given. However, if supplied with true arcs and circles, it will produce genuine arc (G02) moves which the machine controller can then resolve down to whatever level of 'step' its setting may be. …
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I bow to your wisdom, Martin
Yes, as Martin infers, there's a big difference between CAD for Engineering and for "Hollywood" or games.
If you look closely at any curved surface on a game machine you'll see that curved shapes are made of straight lines, but lighting tricks and "texture mapping" can fool the eye.
Despite spending lots of professional work on 3D rendering (ISO standardization, W3C HTML5 work, software distributed by Apple, used by CERN, NASA, and well over a million downloads of my open source package, at last count) I still do 2D CAD for my model engineering.
(mainly, that is. Sometimes I write programs to generate GCODE)
People put down 2D CAD, but as Martin correctly states, the resolution of arcs is down to the machine, not the designer, or the geometry optimizer where rendering time is more important than accuracy of drawn 3D shapes.
Now, 3D CAD can be great, but so can 2D CAD, especially if you have a 3 axis CNC mill, a CNC lathe, or send stuff out for water jet cutting, or laser cutting or…
I guess the expression "use the correct tool for the job" might fit well here. Why not learn both 2D and 3D CAD so you know how to use both tools?
JohnS.