On Feb 20, 2014, at 4:05 PM, Daniel Hyams wrote: > Thanks Sean! I think the problem is my lack of understanding concerning how > BRL-CAD stores its data. I think you're implying that BRL-CAD always stores > its data in a particular unit (mm), so the "units" attribute of a .g file > doesn't matter except as a convenience to the modeler when creating new > geometry?
Exactly. This is done for a variety of reasons, but predominantly for numerical robustness. It helps prevent floating point error accumulation if a modeler simply changes their working units while creating geometry. > I thought that numbers like "500" were interpreted as "500 mm", unless you > had something like "units in" on the second line, in which case "500" means > "500 in". But that's wrong? The get and put commands are special. They're considered low-level, and not generally intended for non-developer use (which is why -- I believe -- they also do not have documentation). They always work in database units (i.e., mm). The 'in' command and most other creation/editing commands are affected by a change to the working units. Cheers! Sean ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk _______________________________________________ BRL-CAD Developer mailing list brlcad-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/brlcad-devel
