[OpenSCAD] Difference between modelling with Openscad and Freecad
adrianv
avm4 at cornell.edu
Thu Oct 3 08:03:27 EDT 2019
In my experience, the answer to your question is that you want to do some
kind of rounding or edge treatment that finishes before the heat death of
the universe---or maybe just part of the model needs to be rounded. So
minkowski() is out. I made a model based on a sine wave shape. The model
wasn't designed around some spec that required certain dimensions for
everything, so some things were arbitrary, but I still wanted to round off
those arbitrary ends. I'm not saying it can't be done, but you're going to
need calculus and you might potentially need to solve a transcendental
equation, which means you need to implement an iterative solver (e.g
Newton's method using tail recursion) unless you want to just hard code
values.
Just knowing the location of the intersection may not be enough to solve
problems like this in general. At least in principle, when I 3d print
something every edge should be rounded unless a specific functional reason
requires a sharp edge. It would be nice if doing this wasn't so difficult.
nophead wrote
> I just don't come across that in practice. If an object has an important
> dimension, that is usually input parameter of the object, so even if it is
> created with an intersection, or a difference, the part that does the
> removal has to be positioned so that it gives the required important
> dimension. That may need some trig but it is never more than I learned at
> high school 40 years ago and can still remember, so I wouldn't call it
> complex. Just a bit of triq and some circle intersection equations that I
> Google for.
>
> Why would you do some arbitrary intersection and then try to find the
> resulting dimensions?
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