[OpenSCAD] What's your opinion on these criticisms of Openscad?

runsun runsun at gmail.com
Thu Sep 17 13:28:38 EDT 2015


kintel wrote
>> 3 OpenSCAD lacks the powerful capabilities of local coordinate systems.
>> 
> No idea what that means; I’m not familiar with Varkon.

All OpenSCAD shapes start with O=[0,0,0], with the x,y,z in the [1,0,0],
[0,1,0], [0,0,1] directions, resp. That's the only one GLOBAL coordinate
system we have. If we want to make a shape on some point P, we make it on O
first, then move it to P.

A local coordinate system is a coordinate system right on P, such that the
obj can be made directly on P.

This sound redundent if O => P is just a parallel translation. But often
cases are that it requires rotations as well. So in many .scad practices, we
see users in struggle trying to make the rotation/translation right. 

I personally think that this criticism has it's point. In fact, I create my
polyhedron lib entirely in local coordiate system. In my lib, given any 3
points in the space, users can make a shape on that. 

This doesn't mean the OpenSCAD global coordinate system is at fault. In many
many cases, a global system is much quicker and easier to handle, especially
when users want is not complicated, and I believe this is the application
that OpenSCAD is designed for. But if we go beyond some complication level,
a local coordinate system will be very handed. 



-----

$  Runsun Pan, PhD 

$ -- libs: doctest , faces ( git ), offliner ( git );

 tips: hash( 1 , 2 ), sweep , var 

$ -- Linux Mint 17.1 Rebecca x64  + OpenSCAD 2015.03.15/2015.04.01.nightly 




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