Eagle snafu,CIRCLE command

[Robert Baer]

The following commands were tried (no more, and no less):
CHANGE LAYER 121
CHANGE WIDTH 0.0005
CIRCLE (0.496 2.842) (1 0)
Note that last command is EXACTLY from the so-called help; gives
radius of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the result is
exactly the same.
The position of the center does have some effect on this bogus
"diameter".

 

[Robert Baer]

The following commands were tried (no more, and no less):
CHANGE LAYER 121
CHANGE WIDTH 0.0005
CIRCLE (0.496 2.842) (1 0)
Note that last command is EXACTLY from the so-called help; gives radius
of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the result is exactly
the same.
The position of the center does have some effect on this bogus "diameter".

Now files are getting corrupted during editing.
SCR commands now have no VISIBLE effect, but Eagle thinks there has
been a change.
I only know after the fact - which is when all is settled.
Real crap!

 

[Jasen Betts]

Now files are getting corrupted during editing.
SCR commands now have no VISIBLE effect, but Eagle thinks there has
been a change.
I only know after the fact - which is when all is settled.
Real crap!

sounds unusual, more people swear by it that at it. perhaps run a
generic diagnositc like memtest-86+ overnight?

 

[Jasen Betts]

sounds unusual, more people swear by it that at it. perhaps run a
generic diagnositc like memtest-86+ overnight?

oops:

more people swear by it THAN at it.

 

[John S]

The following commands were tried (no more, and no less):
CHANGE LAYER 121
CHANGE WIDTH 0.0005
CIRCLE (0.496 2.842) (1 0)
Note that last command is EXACTLY from the so-called help; gives
radius of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the result is
exactly the same.
The position of the center does have some effect on this bogus
"diameter".

It's doing exactly as it is told. The problem is that the second set of
enclosed numbers (1 0) is NOT the radius, it is a POINT on the
circumference. Notice that your circle's circumference passes through
the point x=1, y=0 in the first case and through x=0, y=0 in the second
case. Of course, it defines the same circle because one circle passes
through both points.

 

[John S]

It's doing exactly as it is told. The problem is that the second set of
enclosed numbers (1 0) is NOT the radius, it is a POINT on the
circumference. Notice that your circle's circumference passes through
the point x=1, y=0 in the first case and through x=0, y=0 in the second
case. Of course, it defines the same circle because one circle passes
through both points.

To follow up with an example, if you want a circle with center at
0.496,2.842 and a 1 inch radius:

* Make sure your grid is set for inches
* CIRCLE (0.496 2.842) (1.496 2.842)

 

[Martin Riddle]

The following commands were tried (no more, and no less):
CHANGE LAYER 121
CHANGE WIDTH 0.0005
CIRCLE (0.496 2.842) (1 0)
Note that last command is EXACTLY from the so-called help; gives
radius of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the result is
exactly the same.
The position of the center does have some effect on this bogus
"diameter".

Looks like the info command does not calculate the radius correctly.
I tried with various placements, only origin placements give the
correct radius.

very Interesting....

Cheers

 

[Robert Baer]

It's doing exactly as it is told. The problem is that the second set of
enclosed numbers (1 0) is NOT the radius, it is a POINT on the
circumference. Notice that your circle's circumference passes through
the point x=1, y=0 in the first case and through x=0, y=0 in the second
case. Of course, it defines the same circle because one circle passes
through both points.

Then explain why the CIRCLE (0.496 2.842) (0 0) gives the *same* results.

 

[Robert Baer]

It's doing exactly as it is told. The problem is that the second set of
enclosed numbers (1 0) is NOT the radius, it is a POINT on the
circumference. Notice that your circle's circumference passes through
the point x=1, y=0 in the first case and through x=0, y=0 in the second
case. Of course, it defines the same circle because one circle passes
through both points.

Well, the "help" indicates that is a diameter...contrary to what you
say. Vary parameters in the second set and see no or little change.

 

[Robert Baer]

To follow up with an example, if you want a circle with center at
0.496,2.842 and a 1 inch radius:

* Make sure your grid is set for inches
* CIRCLE (0.496 2.842) (1.496 2.842)

NOT what the "help" sez....Syntax CIRCLE • •.. [center, circumference]

 

[Robert Baer]

Looks like the info command does not calculate the radius correctly.
I tried with various placements, only origin placements give the
correct radius.

very Interesting....

Cheers

So the work-around would be to generate wanted circle at 0,0 and then
move it to correct place.

 

[John S]

To follow up with an example, if you want a circle with center at
0.496,2.842 and a 1 inch radius:

* Make sure your grid is set for inches
* CIRCLE (0.496 2.842) (1.496 2.842)

NOT what the "help" sez....Syntax CIRCLE • •.. [center, circumference]

Notice it says circumference. Center is a pair of numbers. Circumference
is a pair of numbers. Diameter or radius would be a single number.
Circumference is a POINT (x,y) on the circles CIRCUMFERENCE.

 

[John S]

Then explain why the CIRCLE (0.496 2.842) (0 0) gives the *same*
results.

As I said above, it defines the same circle because both (0 0) and (0 1)
define the (x y) coordinates on the same circle's circumference.

 

[John S]

Well, the "help" indicates that is a diameter...contrary to what you
say. Vary parameters in the second set and see no or little change.

Help says nothing about the diameter. It indicates a coordinate pair on
the circumference.

 

[John S]

Looks like the info command does not calculate the radius correctly.
I tried with various placements, only origin placements give the
correct radius.

very Interesting....

Cheers

I gave an example to show how it is done.

 

[John S]

So the work-around would be to generate wanted circle at 0,0 and then
move it to correct place.

That is one way to do it. But, I gave an example to show you how to do it.

 

[John S]

To follow up with an example, if you want a circle with center at
0.496,2.842 and a 1 inch radius:

* Make sure your grid is set for inches
* CIRCLE (0.496 2.842) (1.496 2.842)

NOT what the "help" sez....Syntax CIRCLE • •.. [center, circumference]

It says ...[center, CIRCUMFERENCE]. That means two sets of coordinates.
Let me try this another way...

What is the radius of a circle whose center is at (0.496 2.842) and
whose circumference passes through (1 0)? Does the same circle's
circumference just happen to pass through (0 0)?

Now try CIRCLE (0.496 2.842) (1.496 2.842) and use the info button to
read the circle's radius. You will see that it is 1 inch. That's because
the circumference passes through (1.496 2.842). As you can see, the
horizontal value 1.496 is one inch greater than 0.496 and the y
coordinate has not changed.

This is the way Eagle has done it for over 10 years. It is not the usual
way CAD programs work, but there you have it.

 

[Robert Baer]

On 12/3/2013 7:31 AM, John S wrote:
On 12/2/2013 9:49 PM, Robert Baer wrote:
The following commands were tried (no more, and no less):
CHANGE LAYER 121
CHANGE WIDTH 0.0005
CIRCLE (0.496 2.842) (1 0)
Note that last command is EXACTLY from the so-called help; gives
radius of 2.884957 and if i try CIRCLE (0.496 2.842)(0 0) the
result is
exactly the same.
The position of the center does have some effect on this bogus
"diameter".

It's doing exactly as it is told. The problem is that the second set of
enclosed numbers (1 0) is NOT the radius, it is a POINT on the
circumference. Notice that your circle's circumference passes through
the point x=1, y=0 in the first case and through x=0, y=0 in the second
case. Of course, it defines the same circle because one circle passes
through both points.

To follow up with an example, if you want a circle with center at
0.496,2.842 and a 1 inch radius:

* Make sure your grid is set for inches
* CIRCLE (0.496 2.842) (1.496 2.842)

NOT what the "help" sez....Syntax CIRCLE • •.. [center, circumference]

Notice it says circumference. Center is a pair of numbers. Circumference
is a pair of numbers. Diameter or radius would be a single number.
Circumference is a POINT (x,y) on the circles CIRCUMFERENCE.

Words from one "radius", words from another "circumference", words
from "help" is "circumference" with ZERO examples.
Results from experimentation so far totally inconsistent with any
interpretation.

 

[Robert Baer]

As I said above, it defines the same circle because both (0 0) and (0 1)
define the (x y) coordinates on the same circle's circumference.

Dew tell.
Draw a circle with center at x=0.496, y=2.842 and circumference
crossing x=0, y=0.
What is the radius? Hint: SQRT(0.496^2 + 2.842^2) or about 2.885.
Now draw a NEW circle with center at x=0.496, y=2.842 and
circumference crossing x=0, y=1.
What is the radius? Hint: a circle of about 1.819 radius; leave
calculation to the student.

 

[Robert Baer]

Help says nothing about the diameter. It indicates a coordinate pair on
the circumference.

Isn't the radius of a circle one half of the diameter?
In any case, it talks about the circumference in one breath and the
radius in another breath.