I just answered a question about the -D switch to the openscad command line tool. Then I noticed something that I had never noticed before. Lets take a very simple script: x = 1; // 100 y = 1; // 50 z = 1; // 10 echo("x = ", x); echo("y = ", y); echo("z = ", z); If I open this up in openscad, everytime I change the value of a variable (x say), and then do a preview, it does what I expect it to, change x = 100; then it echos x = 100 BUT: If I call it on the command line with the -D arg, then no matter what I change the value to, it does NOT change the result! EVER! like so: openscad -D x=100 -D y=50 -D z=30 testvar.scad & very Interesting! why? Jerry -- Extra Ham Operator: K7AZJ Registered Linux User: 275424 Raspberry Pi and Arduino developer *The most exciting phrase to hear in science - the one that heralds new discoveries - is not "Eureka!" but "That's funny...".*- Isaac. Asimov *I* *f you give someone a program, you will frustrate them for a day; if you teach them how to program, you will frustrate them for a lifetime. *- Anonymous *If writing good code requires very little comments, then writing really excellent code requires no comments at all!*- Ken Thompson

Jerry, maybe you are expecting -D x=100 test.scad to provide a default value for x, to be overridden by a definition of x within test.scad. But that's not what -D is supposed to do. Instead, -D is used when you want to override a definition in the source code using the command line, which is very useful when you are invoking openscad non-interactively. You are using -D and at the same time invoking scad interactively, which is not the use case for which -D is intended. On 7 August 2015 at 21:21, Jerry Davis <jdawgaz@gmail.com> wrote: > I just answered a question about the -D switch to the openscad command > line tool. > > Then I noticed something that I had never noticed before. > > Lets take a very simple script: > x = 1; // 100 > y = 1; // 50 > z = 1; // 10 > > echo("x = ", x); > echo("y = ", y); > echo("z = ", z); > > If I open this up in openscad, everytime I change the value of a variable > (x say), and then do a preview, it does what I expect it to, change x = > 100; then it echos x = 100 > > BUT: > > If I call it on the command line with the -D arg, then no matter what I > change the value to, it does NOT change the result! EVER! > > like so: openscad -D x=100 -D y=50 -D z=30 testvar.scad & > > very Interesting! why? > > > > > Jerry > > -- > Extra Ham Operator: K7AZJ > Registered Linux User: 275424 > Raspberry Pi and Arduino developer > > > *The most exciting phrase to hear in science - the one that heralds new > discoveries - is not "Eureka!" but "That's funny...".*- Isaac. Asimov > > *I* > *f you give someone a program, you will frustrate them for a day; if you > teach them how to program, you will frustrate them for a lifetime. *- > Anonymous > > > *If writing good code requires very little comments, then writing really > excellent code requires no comments at all!*- Ken Thompson > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > >