GC-Prevue Jump to Component
David Novak
GC-Prevue? Whenever I use Jump to Component, I get the message "Can't
find a component called xx", where xx is the reference designator I am
trying to locate.
It appears that GC-Prevue does not have the reference designator
information that it needs.
Thanks,
David
Stuart Brorson
: Can anyone tell me how to get reference designator information into
GC Prevue is a Gerber viewer. Gerbers are files which tell a
photoplotter how to draw lines and shapes. A Gerber file has no
independent concept of a component or a refdes. As far as a Gerber
file is concerned, the thing which you see as a refdes is just a bunch
of lines drawn in one of your files. Therefore, GC Prevue can't
jump to a component since it has no concept of what's a component and
what is not.
I don't know why GC Prevue has a "jump to component" menu item, but I
suppose that if you use a more sophosticated cam file (ODB++ or
something like that), then GC Prevue knows what to do. Or maybe if
you provide additional information to GC Prevue, then it can
understand that a bunch of lines and apertures is really a component.
But I don't know how you would input that information into GC Prevue.
In any event, plain Gerber is too dumb a file format [1] to hold the
information you want.
Stuart
[1] I am not saying that it is a bad or unintelligent file format.
Rather, it is "dumb" in the sense that it doesn't hold any more info
than simply how to draw lines.
David Novak
> But I don't know how you would input that information into GC Prevue.
> In any event, plain Gerber is too dumb a file format [1] to hold the
> information you want.
>
That was my understanding as well, but since GC-Prevue has the jump to
component feature, I assume there is a way to tell it about reference
designators.
I didn't see a way to import an ODB++ file. What other file format might
be useful for telling GC-Prevue how to interpret the lines in the drawing?
Thanks,
David
Joerg
This may be a bit far-fetched but it could theoretically do that by
OCR-reading the designators off the silk screen layer(s). I'd doubt it
though, considering that it can't even display layers in "see-through"
style. Other than that it's a nice program.
--
Regards, Joerg
Joerg
Just went to the Graphicode web site because a client of mine will soon
need a Gerber viewer. I also checked out the higher (not free) versions.
Lo and behold GC PreView Plus does have silkscreen OCR. Pretty cool. But
it seems a bit pricey at $495.
Brad Velander
I believe you are correct. With additional work from the user, GC-prevue
can probably be instructed as to what constitutes each component. Grouping
the particulary Gerber data back into a component for the purposes of
reverse engineering Gerber data.
Even if GC-Prevue doesn't support components, it would be very likely
that their full feature version sold to fabrication shops would.
--
Sincerely,
Brad Velander.
Joerg
> Stuart,
> I believe you are correct. With additional work from the user, GC-prevue
> can probably be instructed as to what constitutes each component. Grouping
> the particulary Gerber data back into a component for the purposes of
> reverse engineering Gerber data.
>
> Even if GC-Prevue doesn't support components, it would be very likely
> that their full feature version sold to fabrication shops would.
Doesn't need extra work. It's commonly done via silkscreen OCR. The full
feature version of GCPreview appears to have that.
Hawker
Interesting.
I wish CAM350 had that. Oh well.
That is the first REAL usable feature that I have heard from that
product that I could not do in CAM350
Hawker
Joerg
Question: Does CAM350 have semi-transparent layer representation so you
can see through to at least one layer down? None of the viewers I tried
had that. Beats me why because it is a rather mundane but critical
feature. Without it one has to constantly hide/unhide layers. I've got a
huge layout coming and I am always thankful when I made it through one
without carpal tunnel problems.
Brad Velander
But how does a silkscreen OCR know which other Gerber elements to tie
together making a whole component once more. A designator does not make a
component. Sorry, there is no automatic feature that could reliably do that
for all component types, mountings, considering varied silkscreen practices
and hidden designators. There is more to making a component then just
reading a silkscreen designator, a designator is a designator not a
component.
--
Sincerely,
Brad Velander.
"Joerg" <notthis...@removethispacbell.net> wrote in message
news:KhmZh.3909$H_....@newssvr21.news.prodigy.net...
Joerg
> Joerg,
> But how does a silkscreen OCR know which other Gerber elements to tie
> together making a whole component once more. A designator does not make a
> component. Sorry, there is no automatic feature that could reliably do that
> for all component types, mountings, considering varied silkscreen practices
> and hidden designators. There is more to making a component then just
> reading a silkscreen designator, a designator is a designator not a
> component.
Gerber files should generally not be edited and that is not what David
wanted to do. AFAIU he wants to be able to quickly go to C172 or U56 to
see how they are routed, without a priori knowledge of where they are.
Making components should always happen in CAD and then the Gerbers get
generated when this process is complete. In my case I never do layouts,
I contract that out. If my Gerber viewer had silkscreen OCR that would
greatly help me in hopping to the critical nodes. I guess that's also
what David is after. Unfortunately this currently means having to shell
out $495 which I find a bit steep since I don't need the editing
features. Oh well, there's other OCR programs, even my office scanner
came with one.
Hawker
Yes Hitting "t" toggles transparency mode.
Download it and try. They give you a full 30 license to try it for free.
Hawker
Joerg
Thanks. Well, I need something that works for more than 30 days. Instead
of a price they only posted a phone number, which typically leads to the
usual high-$$ haggle. Their CAMvu can't read Gerbers but I found a link
where they mentioned that there is a stripped down CAM350 version sans
editing capabilities. That's all I need. This is the link if anyone else
is interested:
http://www.downstreamtech.com/CAM350/CAMvu.html
Brad Velander
My comments were specific to reconstructing (reverse engineering if you
prefer) components from Gerber data. Yes I would never design components in
Gerber given a ACD alternative but there is a lot reverse engineering that
goes on even within a single company's older files.
I still don't see a great deal of usefulness in the silkscreen OCR
because as I mentioned designators are a quickly dying breed in most
designs. Initially I was probably also concentrating on the command that
David mentioned, "Jump To Component", thus made me think of reverse
engineering the Gerbers to reconstruct components prior to reading the
Gerber back into a CAD system for further edits/design.
--
Sincerely,
Brad Velander.
"Joerg" <notthis...@removethispacbell.net> wrote in message
news:llJZh.3312$HX7....@newssvr19.news.prodigy.net...
Joerg
> Joerg,
> My comments were specific to reconstructing (reverse engineering if you
> prefer) components from Gerber data. Yes I would never design components in
> Gerber given a ACD alternative but there is a lot reverse engineering that
> goes on even within a single company's older files.
>
> I still don't see a great deal of usefulness in the silkscreen OCR
> because as I mentioned designators are a quickly dying breed in most
> designs. Initially I was probably also concentrating on the command that
> David mentioned, "Jump To Component", thus made me think of reverse
> engineering the Gerbers to reconstruct components prior to reading the
> Gerber back into a CAD system for further edits/design.
>
I don't think designators will die out. On the denser SMT boards with
0402 that we do mostly there will be no silkscreen on the top. But it is
still generated by the layouter. I don't really see any other way for an
expedient layout check. Same for troubleshooting, proto-assempbly etc.
Hawker
For the boards that are so dense you can't read the silk screen or there
is no silk screen, the jump to component is even more important.
I often put the Ref Des on another non-printed layer. A assembly layer
or some such in the center of the component. This gives me two
ref-designators. One in the center on a 2nd assy layer and one on the
silk layer (that is often poorly placed due to density).
The next part of that is tool specific. I use PADS PCB and CAM350. I
export from PAD PCB to CAM350 using the CAM export feature. From the CAM
file I can export Gerbers or just leave it alone as intelligent gerbers
in the CAM format. Think of this as Gerbers with component and net
info. I then give my clients the free CAM350 viewer and if they can't
figgure out where a component is from the silk they can use CAM350 to
jump though the gerbers to look for the component.
Hawker
Joerg
Yes, that's what I mean, a non printed layer. It really helps when doing
a dozen boards by hand somewhere.
> The next part of that is tool specific. I use PADS PCB and CAM350. I
> export from PAD PCB to CAM350 using the CAM export feature. From the CAM
> file I can export Gerbers or just leave it alone as intelligent gerbers
> in the CAM format. Think of this as Gerbers with component and net
> info. I then give my clients the free CAM350 viewer and if they can't
> figgure out where a component is from the silk they can use CAM350 to
> jump though the gerbers to look for the component.
>
My layouter uses PADS as well but delivers Gerbers and pho files right
away. He is doing a layout for me right now and this time we do the
back-and-forth via screen shots. But will have to move over to pho
pretty soon as density to board size is a bit thick.
But I shall not complain. Just think about it: 20 years ago we were
doing the Rubylith and razor blade thing. Now we open an email
attachment on our laptops and do the layout check while at a coffee
shop. The only downside is that we sit too much and move too little.
Hawker
> My layouter uses PADS as well but delivers Gerbers and pho files right
> away. He is doing a layout for me right now and this time we do the
> back-and-forth via screen shots. But will have to move over to pho
> pretty soon as density to board size is a bit thick.
>
If your layout dude is using PADS then ask him what version.
Most PADS versions can do a CAM350 Export. Apparently somewhere in V2005
they broke this and fixed it again in 2007 (I'm using 2004).
(tools/CAM350 / create file only / CAM Documents including parts and nets)
If you can get a CAM file you may find this better than checking gerbers
or screen shots.
You can get a free CAM viewer from downstream technologies (see other
link in this thread). In this way you can view his PADs database, nets,
components etc with more intelligence than gerbers, but actually be
looking at the final gerbers. This is way better than looking at gerbers
or screen shots and easier for both you and the layout dude.
Hawker
Joerg
Looks like his can't, it'll all be regular Gerber. But that's ok, so far
the bitmap format works fine for us.
Hawker
If he is using PADS then there should be no reason why he can't export
CAM350 files, unless he does not know how. You must have all your CAM
(PADS word for Gerber Generating scripts) written before you attempt the
CAM350 export though.
Hawker
Joerg
My layouter is pretty well versed with PADS but right now I don't want
to bother him with too many detailed questions. This layout is one of
those fast track projects. Don't we all love those?
He said he prefers to generate the big stack of files at the end and not
bother investing that time right now. Which is fine for me as long as
the bitmaps provide all the info I need for communicating with him.
