Mail Archives: geda-user/2015/03/27/21:25:00
On Sat, 2015-03-28 at 01:35 +0100, Kai-Martin Knaak wrote:
> Peter Clifton wrote:
>
> > Out of curiosity, what is your need / requirement for the 3D view? There
> > are many possible reasons and I'm curious what people actually want.
> Well, you certainly know what I want: A reliable way to communicate pcb
> data to my 3D CAD application and back. This should include positions and
> orientation of components. The use case is straight forward -- make sure
> that the end product fits into its enclosure.
> In this scenario a nice 3D preview comes almost automatically as a bonus.
It occurred to me that many people looking for 3D support might not
actually have access to fully fledged mechanical CAD. I do at one of the
places I work, but not at home, or on Linux (until now*).
*(Free onshape.com account).
NB: FreeCAD isn't quite there for me yet, and likely won't be at least
until its assembly module comes together.
The fact I'm interested in interacting with mechanical CAD means I
favour STEP, but I'm wondering how accessible that is to everyone.
BTW..
One issue I have is the need to reconcile PCB footprint placement with
the 3D component model origin and orientation. I want to assume the STEP
file has the correct coordinate units and scaling (for sanity), but one
must map the origin coordinate / system location between the STEP model
and the PCB model.
It would be nice if every model followed a convention for which of X, Y
and Z were in each direction, and its origin matched the footprint's -
but that will never be true for all arbitrarily sourced models.
To do this without some kind of viewer application (or helper in the CAD
program) would involve iterating test exports, loading into CAD,
measuring offset / orientation, correcting the footprint -> 3D mapping
(whatever form that takes), then re-testing.
[snip]
> Once in freecad, the road is open to STEP, IGES or VRML. So you could turn
> to blender or povray for polished rendering. Or you could do your actual
> 3D design in solidworks or inventor. Since freecad is fully scriptable,
> this would not need to involve starting the freecad UI.
Emit STEP, open that in freecad. (My preference). Working on it..
slowly! I'll see if I can make some progress this weekend.
povray doesn't import STEP, and in general IIRC is not trivial to import
models into. I looked at this for an intern at work who was using povray
to simulate some things for us, and the data-path we got to work was:
Solidworks model (or STEP model, whatever) -> STL -> Stltools (stlL2pov)
-> povray.
I vaguely recall it was "fun" making stl2pov (a python command line
tool) work under Windows 7.
Peter
> ---<)kaimartin(>---
> PS: I can't help to note the coherent style and readability of their
> documentation. You may also take a look at the start page
> http://www.freecadweb.org/
> IMHO, the mix of presentation and documentation is exemplary in many ways.
Pretty nice, yes.
Peter
--
Peter Clifton <peter DOT clifton AT clifton-electronics DOT co DOT uk>
Clifton Electronics
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