Antimony – A fresh look at CAD software

Post by jjoonathan » Fri, May 29, 2015, 2:12 PM UTC

alkonaut wrote: post #45

colomon wrote: post #27

Okay, I'm a CAD software developer instead of an actual CAD engineer, so my perspective may be a bit biased. But this CSG (constructive solid geometry) idea is not in any way new. The reason it's kind of obscure now is that spline-based boundary representation systems (B-reps) took over the market decades ago. If you think about, say, the latest car designs, those free-flowing shapes are pretty easy to do in B-rep, a…

Well, those shapes are hard to accomplish with a CSG of primitive shapes at least. This isn't really "plain CSG" though. I think it uses distance fields (a tree of distance functions), which can be of any kind. The simples ones are just primitives, but anything that has a defined distance could be used, including parametric surfaces, fractals... (If you are using it for actual CAD and not just visualization, you prob…

Post by alkonaut » Fri, May 29, 2015, 2:44 PM UTC

jjoonathan wrote: post #51

alkonaut wrote: post #45

Earlier quoted context omitted.

Well, those shapes are hard to accomplish with a CSG of primitive shapes at least. This isn't really "plain CSG" though. I think it uses distance fields (a tree of distance functions), which can be of any kind. The simples ones are just primitives, but anything that has a defined distance could be used, including parametric surfaces, fractals... (If you are using it for actual CAD and not just visualization, you prob…

Yeah, but how difficult is it to make a distance field with the same versatility as a spline which lets you drag its surface, explicitly add seams of lower continuity (which are important out past the second derivative for reflections), shell a surface to uniform thickness, etc? Blending shapes is neat trick but the market cares most about fundamental operations and it seems to me that the fundamentals are harder to…

Post by shasta » Fri, May 29, 2015, 2:46 PM UTC

tiles wrote: post #16

IshKebab wrote: post #15

Having used OpenSCAD, Solidworks and NX fairly extensively, I can say that "code-based" solid modelling systems are good for some specific things - anything that is highly parametric, for example: * Gears and sprockets * Fasteners (nuts & bolts) * Electrical components (ICs, etc) For anything else they aren't at all suitable. It's just a million times easier to be able to click on dimensions on the actual sketch and…

The ideal would be both worlds. 3D editor until you want to go in and change specific relations, which would be specified in code. Like editing an SVG or hand-editing its source, it's useful to have the option depending on your toolset.

Post by dekhn » Fri, May 29, 2015, 2:56 PM UTC

niklasni1 wrote: post #18

IshKebab wrote: post #15

Having used OpenSCAD, Solidworks and NX fairly extensively, I can say that "code-based" solid modelling systems are good for some specific things - anything that is highly parametric, for example: * Gears and sprockets * Fasteners (nuts & bolts) * Electrical components (ICs, etc) For anything else they aren't at all suitable. It's just a million times easier to be able to click on dimensions on the actual sketch and…

I really like the idea of OpenSCAD, but the language is just unacceptably crappy. It's still better for me with my habits than anything graphical, though. If it had better capabilities for abstraction I think it'd much more suitable for large, complicated objects than a graphical editor.

Post by creeble » Fri, May 29, 2015, 3:09 PM UTC

brudgers wrote: post #56

smoyer wrote: post #35

Earlier quoted context omitted.

And Auto-CAD had a Lisp engine in the '80s ... You could automate almost any function of the drawing system, build "macros" as well as patterns and even alter the DXF generation.

AutoCad got AutoLisp as an update to R6 in January 1986. AutoCad got solid modelling in R11 with the "Advanced Modelling Extension" add-on in 1990. The whole history of AutoCad's feature evolution is that of a successful startup. There's an overview on AutoDesk's website: http://autodesk.blogs.com/between_the_lines/autocad-release-...