[OpenSCAD] Fusion360 and OpenSCAD

Carsten Arnholm arnholm at arnholm.org
Sat Oct 8 11:36:47 EDT 2016


On 08. okt. 2016 15:49, Jerry Davis wrote:
> Carsten: Nice work documenting this.
>
> I had no idea about the nice curving options.
>
> You seem to know quite a bit about this tool:
>
> Do you know what the button on the right does (brings up the url and
> file option)? And how to use it?
>
> How do you add points that you want to be in between two other points
> instead of adding the point at the end?

Hi Jerry,

Well, I had not seen the tool before, I am just able to guess :-) Now I 
guessed what the file option is all about: You are supposed to pick up 
an image file to use as background for manual sketching.

At first I tried an OpenSCAD source file ... I thought perhaps it could 
read a polygon as well as write one, but then it complained that the 
file I gave it wasn't an image. That gave me a hint it wanted an image :-)

So I tried the Ford logo image file (.png) and it worked
https://gyazo.com/094c5662fa9aea39373a0b9b811d9c10

The window that says "Paths" allows you to define several individual 
paths (a.k.a. polygons) in the same sketch, click [New] to start a new 
path. To do the Ford logo example manually it means 4 different 
polygons/paths.

- outer contour of the letter "F"
- inner contour of the small loop in the letter "F"
- outer contour of the letters "ord"
- inner contour of the letter "d"

So in theory you could sketch the logo by tracing the image manually, 
but it gets complicated/tedious and inaccurate. It is much better to use 
an automatic tool when possible. For simpler stuff I guess it could 
work, or if the image is not directly suitable for automatic analysis 
(some are not).

Apparently, there is no way to use the GUI to add points in between to 
other points, or at least I could not figure it out. You can always 
insert the extra point by typing in the correct place in the tiny 
"OpenSCAD code" window, then the curve will be updated correctly. 
However, this to some degree defeats the purpose of the tool, because 
you are then back to editing the source directly, just in a much smaller 
window than usual....

I also tried pasting polygon code from OpenSCAD into the code window, 
but that failed when the coordinates were outside the window range, the 
polygon builder does not fit the coordinates automatically, and it does 
not understand scale() or other transformations. It just not usable for 
too large or too small coordinates. It also turns out that the 
definition of "too small" and "too large" is unclear, I opened the 
polygon builder in Firefox on both Windows7 and Kubuntu 15.10, for some 
reason the x-range is [-72,72] on Kubuntu and [-88,88] on Win7, so when 
I copied a polygon from polygon builder from Win7 to Kubuntu, parts of 
the polygon were hidden under the toolbox and I could not reach it.

It is a nice idea, but with clear limitations.

Carsten Arnholm





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