gEDA-user: 3D PCB data formats and apps

[John Griessen <john@xxxxxxxxxxxxxx>]

Peter Clifton wrote:
> On Fri, 2009-10-02 at 00:27 +0000, Kai-Martin Knaak wrote:
\cairo-rendered onto a texture, then stretched onto a
>>> quad).
>> IMHO, this is cheating. .
.
.
> IMO, this is _not_ cheating, it is a standard technique. 

[jg]Right.  The textured quadrilaterals method gets you an accurate overlapping of edges, and as
you rotate it, the "movie" that is played registers on your mind so you
can see any tight clearance places.  It may not look as perfect as ray-traced,
but post processing can handle that desire.

===

Gareth Edwards wrote:
 >> Let's say the objective of the 3D effects/output in PCB were to test
 >> against a 3D model of the whole system--- not just to visualize the
 >> (populated) PCB.  Would Blender be the right output format then?
 >
 > I guess it depends what your goal is..

[jg]This fits my goals for enclosure clearance and connector clearance
checking -- blender IS my CAD app.
Along with measure functions and use of a grid, blender is fine for mechanical
or architectural CAD.  Architectural components such as windows and stairs
are getting created as blender parameterized model libraries already.

STEP models for components would be great to put with library parts on gedasymbols.org.
Outputting straight blender format for a whole board design would make sense
since blender is open and readily available debian and Red Hat packages.

 > Having said that, I think it could be possible/desirable/cool to use
 > the Blender game engine as the mechanism to work with an interactive
 > view of the assembly,

[jg]That would allow showing movable parts clearances as well.  Blender does linkages,
making it an open platform suitable for robot design.  That function won't likely be in any
architectural app any time soon.

===

andrew whyte wrote:
 >   It might sound like eye-candy,  but I can't help but feel like
 > sometimes being able to rotate the pcb stack as we would in any 3D CAD
 > program and view it from another perspective would be an awesomely
 > powerful feature.

[jg]Yes, that would go beyond "nifty" and help find subtle mistakes.

===
joeft wrote:
Putting aside for a moment the lack
of appropriate models
etc., I was impressed by how easy it was to adjust the view (rotation,
zoom, position ...) with this tool.  (Sweet Home 3D)
  "3D models of OBJ, LWS or 3DS formats supported by the furniture import wizard of Sweet Home 3D"

[jg] I like this...and it supports import from sites like gedasymbols.org exterior to their
architectural project.  The "house" drawn could be a circuit and enclosure with components as "furniture"!
The project is free and open and alive.

==

andrew whyte wrote:
  I've simply never had time to go back and build or find 3D
 > models of every custom component on my board
.
.
.
  But some 3D cad interaction would be great!
.
.
.
  rather than going down the route of
 > needing schematics symbols, footprints and 3d models for each
 > component in a design, could we add a "height" attribute to the
 > schematics (this wouldn't be a big job for the designer using
 > gattrib).  Then if someone could script something that takes the board
 > outline, and adds block shapes based on the PCB footprint (outline)
 > and the height for each component,  the results would be a viable 3D
 > skyline that would be workable from a CAD perspective, low
 > maintenance, and would also give you an idea of the 3D system.

[jg]This sounds fabulous. We've all heard how heavy symbols and annotated footprints
are a never ending always incomplete project, so height boxes as a fall-back default
is great!   Another thing we should think more about is how to define  a standard 3D
origin point for footprint data, and how to fix broken ones easily in place by changing
an attribute that will cause the footprint to shift and then require moving it to repair an existing
layout, but then allow good accurate depiction of 3D and pick and place footprint volumes in space.

John Griessen
-- 
Ecosensory   Austin TX


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