5 Jun
2013
5 Jun
'13
9:04 a.m.
On 06/05/2013 09:48 AM, David Riley wrote:
I am given to understand that some CAD systems let you input
coordinates numerically. So, yes, in principle!
Well, yes, in principle. It's not *efficient*, but it is available.
Sometimes, it's even the right thing to do; in board layout, I typically
numerically position the board outlines because they usually have to fit
a numerically-specified mechanical drawing. If I had to do that for all
the components on the board, though, I'd go mad, and it's fairly easy to
do pixel-exact placement when you're just lining things up (assuming you
have standard ~72dpi pixels; these newer "retina" displays change that a
bit).
In mechanical CAD, where nearly all shapes' dimensions are as critical as a
PCB's outline drawing, it is very common to enter coordinates (in native
units) via the keyboard. I'd even call it the norm.
I only do it for the type of placement that you mention above; stuff that
has something to do with (say) screw holes or component placement to mate
with a chassis. But the M.E. people that I occasionally work with use direct
coordinate entry for pretty much everything. They use AutoCAD and
Solidworks. Solidworks does it differently; you draw something directly and
then constrain it by entering its dimensions. In AutoCAD, you start to draw
an object and it prompts you for the dimensions. You can actually do an
entire drawing in AutoCAD via text input. It'll take forever, but it'll be
dimensionally perfect! ;) (modulo typos of course!)
I dated a commercial architect for a long time, ending a few years ago.
She designed things like hotels and shopping malls, using AutoCAD with the
ADT extensions. Most of her job involves entering coordinates manually as well.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
Real
keyboards!
For pixel-accurate pointing on a CAD drawing?