example attached where a fillet is created:
calculations for this are done in python.
[image: Screenshot 2023-07-22 at 9.41.49 PM.png]

On Sun, 23 Jul 2023 at 21:37, Sanjeev Prabhakar sprabhakar2006@gmail.com
wrote:

On 23.07.23 18:34, Sanjeev Prabhakar wrote:

That is great stuff, but in my view it would belong into the geometry
engine.

Maybe you can help with the calculation side of that?

ciao,
Torsten.

On Sun, Jul 23, 2023 at 09:37:10PM +0530, Sanjeev Prabhakar wrote:

I agree that a procedural language addition to openscad would be very
useful. Some things are much easier to express procedurally than the
way openscad would like you to formulate things.

For example building up an array element by element is awkward in
openscad, while "natural" in a procedural language.

It took me a long time to figure out why a module using a global
variable wouldn't instantiate in two different ways when I changed the
global variable between calls. (back then openscad didn't have the
warning that is generated nowadays).

I agree with the openscad folks that it is an advantage that an
openscad script is just "data": It cannot affect your computer beyond
bogging it down for a while while trying to render it. Just like a
"word processor documuent" should be.

How about allowing the python extension to be activated by a
commandline argument but also by using a different binary name.

pyopenscad, popenscad or maybe openpyscad. (That last one... might not
be such a good idea... ). And a different extension.

For those that are paranoid (and those that don't have python at
compile-time) it should remain possible to compile without python
support.

I'm hoping such a construction would satisfy both ends of this
discussion.

Roger.

--
** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
**    Delftechpark 11 2628 XJ  Delft, The Netherlands.  KVK: 27239233    **
f equals m times a. When your f is steady, and your m is going down
your a is going up.  -- Chris Hadfield about flying up the space shuttle.

Thanks

It's a little complicated to explain,  but the main thing is calculating
the intersection line between 2 solids.

Once you get the intersection line,  then it's not so difficult to create
any fillet.

On Sun, 23 Jul 2023, 22:16 Torsten Paul, Torsten.Paul@gmx.de wrote:

On Sun, Jul 23, 2023 at 06:45:41PM +0200, Torsten Paul wrote:

This specific case of "a fillet" is something that might be welcome in
openscad. But that is not the point that Sanjeev is trying to make.

There are manythings that are relatively easy to do in
python-enhanced-openscad, that are hard to do in vanilla openscad. Not
just fillets. His example might make sense to "Oh, but we want that to
be possible in plain openscad". You can't keep saying that for
everything that anybody can come up with.

Roger. 

--
** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
**    Delftechpark 11 2628 XJ  Delft, The Netherlands.  KVK: 27239233    **
f equals m times a. When your f is steady, and your m is going down
your a is going up.  -- Chris Hadfield about flying up the space shuttle.

On 23.07.23 18:59, Sanjeev Prabhakar wrote:

I have not looked at the details, but my understanding from some discussion
in the Manifold repository is there are IDs in the CSG output that detail to
which part the new faces belong. From that it should be possible to get the
information which vertices are that intersection line.

Maybe we can try some demo code separate from OpenSCAD to see if we can get
your algorithm into Manifold based C++ code.

ciao,
Torsten.

On Sun, Jul 23, 2023 at 10:29:34PM +0530, Sanjeev Prabhakar wrote:

I'm guessing that it can become complicated.
Try this:

fillet_radius = 3;
dist = 10;
size = 10;

fillet (radius= fillet_radius) {
cube ([size2+dist, size, size]);
cube ([size, size, 2size]);
translate ([size+dist, 0,0]) cube ([size, size, 2*size]);
}

Easy. But what if dist is reduced to below 2*fillet_radius ? You can
intersect the radii but then you'll get a sharp inside corner that the
fillet is supposed to be preventing.

And what if dist is reducted to below 1*fillet_radius ? Does the space
between the objects fill completely with fillet?

In the general case, this is quite hard.

Roger. 

--
** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** +31-15-2049110 **
**    Delftechpark 11 2628 XJ  Delft, The Netherlands.  KVK: 27239233    **
f equals m times a. When your f is steady, and your m is going down
your a is going up.  -- Chris Hadfield about flying up the space shuttle.

On 23.07.23 18:59, Rogier Wolff wrote:

The related logic is already merged into OpenSCAD master and the
PR adding the actual Python interface is accepted in spirit, just
pending some detailed code review. So it's only a matter of finding
the time, no general open discussion.

https://github.com/openscad/openscad/pull/4702

Getting builds to enable this feature is going to be a challenge,
as I mentioned before, but we'll have to see if we can get some
help with that.

ciao,
Torsten.