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

Tom.Nally at shell.com Tom.Nally at shell.com
Thu Sep 17 13:34:26 EDT 2015


Say that you create a tall, slender cylinder in OpenScad, one whose height is perhaps 4 times larger than its diameter.  At the time of the cylinder's creation, the global axes and the cylinder's local axes will be identical, with the local z- and global-z axis lying along the longitudinal axis of the cylinder.

Now say that you rotate the cylinder 45 degrees about the global x-axis.  The global x-axis and the cylinder's local x-axis still remain the same after the rotation.  However, the cylinder's local z-axis will rotate along with the cylinder so that it remains aligned with the cylinder's longitudinal axis.  Likewise, the cylinder's local y-axis rotates, too.

You can see why this kind of a feature might be useful (not that I'm arguing for it).  There are some occasions when a designer might want to translate or rotate an object relative the object's local axes rather than the global axes.  For example, if the slender cylinder were a bolt instead, and if the bolt was rotated 45 degrees about the global x-axis, and if you wanted to prepare an animation where the bolt tightens, then you would want to rotate the bolt about its longitudinal axis, which would be its local z-axis.

I suspect that the mathematics for tracking and displaying an object's local axes would be very complex.

In my business (structural engineering) most structural analysis software packages will recognize that each structural member has its own set of local axes, in addition to the global axes that tend to govern for the entire structure.

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

 -Marius


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