Partial circle, straight edges?

On 1/27/2011 4:40 PM, Fredric wrote:

So another high frequency application was this geometric figure I couldn't

make in Eagle.

 

It was supposed to be a 60 degree slice of a circle 15mm radius and 10mm

thick. So 20mm in diameter empty space in the middle of a 40mm filled

circle then

a 60 degree slice of that... Like if you'd cut a slice of a donut.

 

I gave up after about 30 minutes and the best I managed to do was that

figure but ending with round edges. So I asked the guy at the Genesis CAD

software and he fixed it by masking a negative image upon that cirle just

by putting two straight lines from the middle 60 degrees apart and then

just kept the area between these - took two minutes.

 

So if I wanted to do that in Eagle, could it be done? Are there any known

plans of introducing negative images on the top and bottom layer?

 

I guess this is one of the reasons I used Paint or other paint software to

make PCBs images back in the day. You could do anything you wanted quick

and easy.

for the top and bottom layers, the Restrict layers cause polygons to

avoid them. so will signal wires or polygons with different "names". if

you use the arc command you can draw arcs with arbitrary inner and outer

radii and angles. But none of these things are intuitively obvious or

especially convenient in eagle because that is not its purpose. It is

for capturing schematics, and routing complex circuits. when a special

copper pattern is desired, it is possible, even quick once you

understand how eagle thinks, but you can't just sit down to eagle and do

that anymore than you can route a 4 layer board with 5000 nodes in paint

just by sitting down and trying it.

/you need to read the manual/, and practice drawing objects. in eagle,

arcs and lines are the same object. you also need to learn all about

polygons and how to use their 20 or so parameters to get what you want.

learning to use the mark and grid commands the way eagle wants you to is

also helpful. generally, sensitive mechanical stuff is best done from

the command line where exact numbers can be entered, just make sure the

grid is set to finest...i still don't understand under what

circumstances eagle snaps to the nearest grid point and under what

circumstances it obeys the numbers you put in.

also, to get real precision, it would help if you understood that a

Gerber file is: a raster of vectors, like on an old plotter, with a

given pen size. look at a Gerber file in a Gerber viewer with the paths

turned on - it is very instructive to see how shapes are synthesized

from pen ( apertures in Gerber speak) movements.

On 1/27/2011 4:40 PM, Fredric wrote:

So another high frequency application was this geometric figure I couldn't

make in Eagle.

 

It was supposed to be a 60 degree slice of a circle 15mm radius and 10mm

thick. So 20mm in diameter empty space in the middle of a 40mm filled

circle then

a 60 degree slice of that... Like if you'd cut a slice of a donut.

 

I gave up after about 30 minutes and the best I managed to do was that

figure but ending with round edges. So I asked the guy at the Genesis CAD

software and he fixed it by masking a negative image upon that cirle just

by putting two straight lines from the middle 60 degrees apart and then

just kept the area between these - took two minutes.

 

So if I wanted to do that in Eagle, could it be done? Are there any known

plans of introducing negative images on the top and bottom layer?

 

I guess this is one of the reasons I used Paint or other paint software to

make PCBs images back in the day. You could do anything you wanted quick

and easy.

for the top and bottom layers, the Restrict layers cause polygons to

avoid them. so will signal wires or polygons with different "names". if

you use the arc command you can draw arcs with arbitrary inner and outer

radii and angles. But none of these things are intuitively obvious or

especially convenient in eagle because that is not its purpose. It is

for capturing schematics, and routing complex circuits. when a special

copper pattern is desired, it is possible, even quick once you

understand how eagle thinks, but you can't just sit down to eagle and do

that anymore than you can route a 4 layer board with 5000 nodes in paint

just by sitting down and trying it.

/you need to read the manual/, and practice drawing objects. in eagle,

arcs and lines are the same object. you also need to learn all about

polygons and how to use their 20 or so parameters to get what you want.

learning to use the mark and grid commands the way eagle wants you to is

also helpful. generally, sensitive mechanical stuff is best done from

the command line where exact numbers can be entered, just make sure the

grid is set to finest...i still don't understand under what

circumstances eagle snaps to the nearest grid point and under what

circumstances it obeys the numbers you put in.

also, to get real precision, it would help if you understood that a

Gerber file is: a raster of vectors, like on an old plotter, with a

given pen size. look at a Gerber file in a Gerber viewer with the paths

turned on - it is very instructive to see how shapes are synthesized

from pen ( apertures in Gerber speak) movements.