At 03:26 PM 2/4/2002 +0000, Steve Wiseman wrote:
>All is well, except that, when placed at angles
>like 45 degrees, they don't get plotted on the gerbers. (neither the
>copper nor the holes in the solder resist.) Viewmate and my PCB shop

Protel draws rectangular pads when they are rotated. They could do better, 
in general the Protel implementation of RS-274X ... is less than the best.

The pad appears to be drawn with an aperture which is one-fourth the 
smallest dimension of the pad. This makes a rounded rectangle. It is, 
however, a significant deviation from display, a violation of the general 
rule that the gerber should match display (and DRC). Normally, however, 
this difference will not cause board failure (but it could).

All forms of gerber will support accurate drawing, it is rather shameful, 
I'd say, that the ways in which Protel falls down have not been fixed after 
all these years. We could start with octagons, which are flat out incorrect.

Protel does not, in the Knowledge Base, seem to recognize how badly things 
are broken. It is true that *most* PCBs do not contain conditions which 
show plot problems, that's the only reason that the existing situation has 
been tolerable. One Knowledge Base item recognizes, for example, that 
rotated octagons are plotted as circles; it suggests a work-around of 
rotating the individual pads to rotation 0. Which, of course, produces an 
octagon which is rotated 22.5 degrees according to RS-274X, but it appears 
that fabricators know not to follow the standard!

The big problem with this work-around is that the pad edges are no longer 
where they were in the PCB file, and the difference could be significant.

We can hope for better with Phoenix. It's about time that Protel generates 
true and correct RS-274X code. Yes, this will require different routines 
than are used for RS-274D, but along the way positive/negative plane merges 
and the like would become possible. And rotated flashes, I think, though 
RS-274X itself is frustratingly obtuse. Nevertheless, Protel owns CAMtastic 
and *better* get it right!

(CAMtastic also has problems, it does not seem to handle submil features 

Now, to the present problem. Here is what I suggest. Create a board file 
with just one of the pads in question. Plot it. Copy the gerber code into a 
mail to the list. Describe the pad's characteristics fully, also anything 
which might be relevant from the gerber setups.

Since rotated pads *do* plot for me, we need to look for something specific 
about *these* pads.

Abdulrahman Lomax
Easthampton, Massachusetts USA

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