Mentor
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Message 1 of 11 (534 Views)

# What distinction is between “intersection” and “apparent intersection” in snaps,

534 Views, 10 Replies
09-15-2012 03:54 AM

What distinction is between “intersection” and “apparent intersection” in snaps,

I’m not sure what difference is between the “intersection” and “apparent intersection” in snaps.

Thanks

Best

Jamal

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Jamal NUMAN, GIS and Civil Engineer, MSc
e-mail: JamaL9722060@yahoo.com
P.O.Box: 731, Ramallah, West Bank, Palestine.
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Message 2 of 11 (525 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-15-2012 05:29 AM in reply to: JamaL9722060

The 3rd dimension.  In order to intersect, lines must share a common plane.  This stuff is in the help files BTW.

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Message 3 of 11 (513 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

best

Jamal

----------------------------------------------------------
Jamal NUMAN, GIS and Civil Engineer, MSc
e-mail: JamaL9722060@yahoo.com
P.O.Box: 731, Ramallah, West Bank, Palestine.
----------------------------------------------------------
Windows 7 (Ultimate 64 bits),
Firefox 20.0,
Kaspersky 2013.
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Message 4 of 11 (507 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-15-2012 04:42 PM in reply to: JamaL9722060

Apparent intersection absolutely does not have to have a 3rd dimension involved. Intersection is typically used when 2 lines do in fact touch and form an intersection. Apparent intersection is the point where 2 lines that do not touch, would touch if you extended them (assuming they are not parallel, of course). In your drawing, there is currently no intersection between the bottom blue line going to the center of the circle and the blue arc in the upper left. If you tried to draw a line from the intersection of that line and that arc, it would say there is no intersection. But if you tried to draw a line from the Apparent Intersection of that line and that arc, it would start at a point where the line would intersect the arc if you extended the line all the way to the arc. Try it. Draw a line from the Apparent Intersection of that line and that arc and you will see what you get. It's a fantastic o-snap and you will be amazed how much you will end up using it.

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Message 5 of 11 (492 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-16-2012 09:18 AM in reply to: stevev0983

thank you very much for the elaboration.

i couldn't draw a line for the "apperent intersection" on the arc to the line.

i couldn't know what to type on "appoint of and"

and thus i couldn't feel how to get the benifit of the "apperent intersection"

best

Jamal

----------------------------------------------------------
Jamal NUMAN, GIS and Civil Engineer, MSc
e-mail: JamaL9722060@yahoo.com
P.O.Box: 731, Ramallah, West Bank, Palestine.
----------------------------------------------------------
Windows 7 (Ultimate 64 bits),
Firefox 20.0,
Kaspersky 2013.
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Message 6 of 11 (488 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-16-2012 10:16 AM in reply to: JamaL9722060

Hi,

does this video show you the missing link?

- alfred -

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Mentor
Posts: 1,307
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Message 7 of 11 (484 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

Many thanks for the contribution Alfred. I got it now. The video does help capturing the idea fast.

Best

Jamal

----------------------------------------------------------
Jamal NUMAN, GIS and Civil Engineer, MSc
e-mail: JamaL9722060@yahoo.com
P.O.Box: 731, Ramallah, West Bank, Palestine.
----------------------------------------------------------
Windows 7 (Ultimate 64 bits),
Firefox 20.0,
Kaspersky 2013.
*Expert Elite*
Posts: 1,514
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Message 8 of 11 (469 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-16-2012 04:04 PM in reply to: stevev0983

@Steve:

Intersection snap also works when objects do not touch as well but will not work when the objects are not on the same plane.  If an intersection is not found on the first pick, it is deferred, (3 dots).  Only APP will find an apparent intersection between non-coplanar objects. The trouble with leaving APP on is when you have accidental non-coplanar objects, it won't tell you the objects aren't coplanar.  So you can end up creating a mess accidentally.

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Message 9 of 11 (419 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

Thank you for the help Steve. This point is quite important.

All the best

Jamal

----------------------------------------------------------
Jamal NUMAN, GIS and Civil Engineer, MSc
e-mail: JamaL9722060@yahoo.com
P.O.Box: 731, Ramallah, West Bank, Palestine.
----------------------------------------------------------
Windows 7 (Ultimate 64 bits),
Firefox 20.0,
Kaspersky 2013.
*Expert Elite*
Posts: 1,514
Registered: ‎08-16-2007
Message 10 of 11 (404 Views)

# Re: What distinction is between “intersection” and “apparent intersection” in sn

09-18-2012 06:09 AM in reply to: JamaL9722060

You're welcome.  Apparently the question needed asking.

Doug

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