At 03:45 PM 4/30/2002 -0700, Mira wrote:
>The meaning in Pcad is that you get all layers
>swapped. Top goes to bottom, silk top - to silk
>bottom. So it's like looking at the PCB from the
>bottom side (or routing as the bottom side it your top
There are three possible aspects to "mirroring" and "flipping."
Mirroring would not flip the board, it would not convert top to bottom,
etc. Mirroring is useful in generating checkprints of the bottom layer(s),
particularly the legend; it can also be used, in gerber photoplot, to
generate bottom views that can be reimported.
Flipping could mean flipping in view only or flipping in actuality.
View-only flipping would merely mirror the display. It should be relatively
easy for Protel to implement this, but they have not..... View-only
flipping is really the same thing as plot mirroring, except it is with the
display instead of with print or plot output.
Actual flipping is a tad complex; Mr. Wilson, as I recall working with Mr.
Harland, wrote a board inversion server. Full board inversion (we called
this "deep" inversion) would truly reproduce the database as if the board
had been completely flipped. Note that this involves changing inner layer
assignments, it is not merely a matter of mirroring all layers and swapping
the top and bottom layer assignments of primitives.
Deep inversion would primarily be useful with design re-use, I won't go
>Design views of your top and bottom overlay (silk)
>next to your PCB design help you to locate easily the
>components. When you flip the PCB and "refresh" you'll
>see the views changed, too. Highliting a component
>also highlights in in the view. Select another one and
>it appears selected on the view.
Yes, this is a desirable feature. It was originally, if I am correct, a
quite expensive add-on to PCAD. This feature, as I would anticipate it,
would allow the placement of a view of the PCB next to the PCB. This view
might not only be mirrored, if desired, it might also be rescaled; it might
include only a defined section of the design (i.e., to create a detail view).
The existence of this tool or something like it in PCAD reflects the
mission and user base of PCAD: PC design specialists working in large
companies. Protel is aimed primarily at engineers, though there are
certainly large companies using it.
The original price of PCAD -- at the time Protel bought it -- reflects this
difference. PCAD pricing was collapsed almost immediately by Protel to a
flat $10K for the whole shebang, at a time when Protel pricing was still
$6K for a full suite. Protel pricing has now come up a bit to $8K, but we
can expect that this pricing really reflects the new elements that will
appear in Phoenix, since it will include Phoenix when the latter is released.
Bottom line: the (relatively) easy way to make bottom-side-view assembly
drawings is to export appropriate gerber and re-import it; this is how I
have done it and I think Techserv does about the same (they may have
utilities to speed the process, but it is not difficult).
>I've got another question.
>When moving the selection I placed it close to the
>lower left corner... but some of the components are
>now out of the working space. I looked to me it was
>possible to place them there and Protel didn't
>complain. It was deselected and saved in the mean
Naughty, naughty. Yes, Protel allows out-of-workspace primitives. Having
used Tango, which does not allow this, I'd say that I prefer the Protel
way; but Protel should add tools to make it easy to recover such
primitives. Among other things, DRC should report out-of-workspace
primitives; as it is, an out-of-workspace footprint pad will *not* generate
an incomplete net error. I consider that a bug.
There is a clear sign that you have out-of-workspace primitives: Zoom All
will not confine itself to the complete set of primitives that you can see.
The basic method of moving these primitives back into the workspace, where
they can be manipulated and/or deleted, is to place any primitive, like a
large pad, Select All, then Deselect Inside to deselect everything visible
except that pad. Pick up the pad, and when you are moving it, a box should
appear that will extend out of the workspace. By moving the pad, you may be
able to bring in the out-of-workspace objects. I say "may" because
sometimes an object can be so far outside the workspace, as a result of
multiple selected object moves, that it will take more than one move to
bring everything in.
>How may I select again the PCB only? There are many
>other things than I don't want to move.
Protel provides a powerful set of selection tools. I've described above one
way to move only out-of-workspace objects. There are others.
Note that sometimes a component may be basically on-screen but may have an
out-of-workspace primitive. This can make for complications, but it is
still not difficult to fix once one knows the problem. (Such a condition
can come to be through an accidental edit of a pad location, for example;
normally pad locations for footprints are locked out of edit, but one may
unlock them for some purpose and forget to relock....)
To recall some of the discussion in recent threads, one will find oneself
frustrated over and over by expecting Protel to function like other CAD
programs. (This works in the other direction, too.) Generally, however,
once one understands how to accomplish a thing in Protel, it does make
sense, it is relatively easy to remember. It was not this way in OrCAD
Layout v. 7, I don't know about more recent versions, but I expect they
haven't changed much.
As a Tango user, I found it fairly easy to get going with Protel, I was
doing productive work the first day. Protel is, more-or-less, a descendant
of the original Tango and some of the philosophy remains. But Accel PCAD
diverged quite a bit, and so did Protel, I'd expect the move from PCAD to
Protel to be more difficult.
But I also expect Protel to be easier for a new user, unfamiliar with other
CAD systems, to learn; but I do advise any new user to subscribe to this
list and, when frustrated, ask....
One will also learn a lot simply reading the list; this is true even for
experienced users. There are powerful tools that are very easy to use, once
one knows that they are there.....
Loop Removal is an example. Loop Removal, when enabled, allows rerouting a
trace simply by placing a new one over it; the original trace will be
ripped up without any need to delete tracks manually. It does take a little
skill to drive the tool so that the results are usually as desired; this
has been described elsewhere, but suffice it to say that it *can* be driven
in such a way. Loop Removal, used properly, cuts the time to reroute
roughly in half....
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