I am going to take Michael's word that there is no immediate way to do
that, but since you are procedurally generating solids I assume you are no
stranger to some programming.

You may use project(...) to grab a slice from your solid. From the command
line you can then modify a transformation so that project(...) gets a slice
of your interest, and export slices to dxf. Coding a 2D raytracer should be
an order of magnitude easier than a 3D one.

If all you need to know is IF 2 objects are colliding, then you may use
intersection(), export via commandline, and check for a non-empty resulting
STL (filesize maybe?).

If you need to know WHERE they are colliding then again use intersection(),
but this time you will need to parse the output STL and read the
coordinates. Still easier than calculating the collision yourself.
Em 15/06/2016 03:08, "username" atex76@shaw.ca escreveu:

Seems like it would be possible to change the language to create an
intersects() function that returns a boolean

On 6/15/2016 7:34 AM, Lucas Vinicius Hartmann wrote:

lhartmann wrote

This could work, but I doubt OpenSCAD will export an empty STL. So you'd
have to catch some error, which is viable.

There is also a fast heuristic way to do a batched collision test, with no
extra rendering involved

• count the number of vertices v_i and faces f_i in all ingoing STLs and
  v_a, f_i of the combined STL.
• test for sum(v_i) != v_a && sum(f_i) != f_a

Its heuristic, because depending on your problem, there might be a very
small probability to get a false result. This is, when two shapes intersect
and have the same number of vertices AND faces.

--
View this message in context: http://forum.openscad.org/Evaluating-imported-STL-s-tp17682p17688.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

jon_bondy wrote

As I said, NO.

There have/are proposals to...

but now, NO.

Even then, F5 v's F6 (full render) make such proposals reliant on full F6
render, thus losing the advantage of fast development which current F5
provides.

Any such proposals further weaken the current OpenSCAD advantages, which the
progression to things like resize() etc. which denude the F5 performance
advantage.

Admin - PM me if you need anything, or if I've done something stupid...

Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.

The TPP is no simple “trade agreement.”  Fight it! http://www.ourfairdeal.org/  time is running out!

View this message in context: http://forum.openscad.org/Evaluating-imported-STL-s-tp17682p17689.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

lhartmann wrote

You could probably do it with a batch script...

But then you would be better off using a language designed to do the job.

Sorry, I have elevated Grump-Old-Man levels ATM...

Admin - PM me if you need anything, or if I've done something stupid...

Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.

The TPP is no simple “trade agreement.”  Fight it! http://www.ourfairdeal.org/  time is running out!

View this message in context: http://forum.openscad.org/Evaluating-imported-STL-s-tp17682p17690.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

sorry, there was a typo:

• test for sum(v_i) == v_a && sum(f_i) == f_a

Parkinbot wrote

--
View this message in context: http://forum.openscad.org/Evaluating-imported-STL-s-tp17682p17692.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

On 2016-06-15 13:34, Lucas Vinicius Hartmann wrote:

Based on 2 STL files (or better: 2 AMF files), it would be trivially
easy and fast to determine many cases of non-intersection, based on
bounding boxes. However, there will be cases where bounding boxes
intersect but where the bodies still do not intersect. For these cases a
more detailed intersection algorithm is needed.

However, I am not aware of any way something like this can be done in
OpenSCAD.

Carsten Arnholm