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# Tangent Angle Error

Not applicable

In practicing dimensioning, measurements were made for the length of a pulley
belt located on 2 and 4 inch diameters with centerlines 4 inches apart. Using
ZOOM and math analysis, it was found that small position errors could result
unless features were locked. Question is what constitutes locked? The included
file shows initial two attempts with errors followed by a successful third
attempt agreeing with Excel analysis to 7 figures. The fourth sheet investigates
why but only serves to raise the question shown. The angle error indicated is
nearly 3% and is unacceptable. How can the line be tangent without being
perpendicular? Is there error in the program or the drawing shown? How can this
error be avoided?
7 REPLIES

# Re: Tangent Angle Error

Not applicable
I looked at your sketches, and essentially all could be fixed by properly
constraining the geometry. I have attached what was your "second try" and
cleaned it up and simplified it. It is not necessary to use all the
construction geometry. Some of your problems were caused by geometry
overlaid on other geometry which was not connected to what it should have
been.
--
Ken
http://grundey.blogspot.com
"Gil Tellier" wrote in message
news:4568dac1\$1@bbsnotes.ugs.com...
>
> In practicing dimensioning, measurements were made for the length of a
> pulley
> belt located on 2 and 4 inch diameters with centerlines 4 inches apart.
> Using
> ZOOM and math analysis, it was found that small position errors could
> result
> unless features were locked. Question is what constitutes locked? The
> included
> file shows initial two attempts with errors followed by a successful third
> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
> investigates
> why but only serves to raise the question shown. The angle error indicated
> is
> nearly 3% and is unacceptable. How can the line be tangent without being
> perpendicular? Is there error in the program or the drawing shown? How can
> this
> error be avoided?

# Re: Tangent Angle Error

Not applicable

Ken,
Thanks for the sketch. I have attempted to duplicate your results: draw two circles
and tangent lines, trim two inner arcs, dim tangent line and arc lengths, add inner
arcs back concentric, with the results shown in the attachment. I could not produce
green vertical dim line to get tangent angles and 4.00 dims. I also noted a missing
Point on (whatever that is) and an X at the connect points that was on your dwg.
Last, your radial dims seem locked and can be duplicated but not moved. Thanks again
for the help.
Gil Tellier
"PellaKen" wrote:
>I looked at your sketches, and essentially all could be fixed by properly
>
>constraining the geometry. I have attached what was your "second try" and
>
>cleaned it up and simplified it. It is not necessary to use all the
>construction geometry. Some of your problems were caused by geometry
>overlaid on other geometry which was not connected to what it should have
>
>been.
>
>--
>Ken
>http://grundey.blogspot.com
>
>"Gil Tellier" wrote in message
>news:4568dac1\$1@bbsnotes.ugs.com...
>>
>> In practicing dimensioning, measurements were made for the length of a
>> pulley
>> belt located on 2 and 4 inch diameters with centerlines 4 inches apart.

>
>> Using
>> ZOOM and math analysis, it was found that small position errors could
>> result
>> unless features were locked. Question is what constitutes locked? The
>> included
>> file shows initial two attempts with errors followed by a successful third
>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>> investigates
>> why but only serves to raise the question shown. The angle error indicated

>
>> is
>> nearly 3% and is unacceptable. How can the line be tangent without being
>> perpendicular? Is there error in the program or the drawing shown? How can

>
>> this
>> error be avoided?

>
>
>

# Re: Tangent Angle Error

Not applicable
Gil,
I started with two circles set at the radiuses shown, I placed a
Horizontal Connect between the two centers, added the tangent lines on the
side which received both an Point On Connect (the "X") and a Tangent
constraint on each end. To be able to measure the arc length on each
circle, I used the Split Element command to split the circles into arcs at
the endpoint of the lines.

The angle dimensions where placed using the Horizontal/Vertical option and
selecting the center point of the circle and the endpoint of the line (very
important to select the keypoints on the element and not the element in
general).
--
Ken
http://grundey.blogspot.com
"Gil Tellier" wrote in message
news:456a8eac@bbsnotes.ugs.com...
>
> Ken,
> Thanks for the sketch. I have attempted to duplicate your results: draw
> two circles
> and tangent lines, trim two inner arcs, dim tangent line and arc lengths,
> arcs back concentric, with the results shown in the attachment. I could
> not produce
> green vertical dim line to get tangent angles and 4.00 dims. I also noted
> a missing
> Point on (whatever that is) and an X at the connect points that was on
> Last, your radial dims seem locked and can be duplicated but not moved.
> Thanks again
> for the help.
> Gil Tellier
>
> "PellaKen" wrote:
>>I looked at your sketches, and essentially all could be fixed by properly
>>
>>constraining the geometry. I have attached what was your "second try" and
>>
>>cleaned it up and simplified it. It is not necessary to use all the
>>construction geometry. Some of your problems were caused by geometry
>>overlaid on other geometry which was not connected to what it should have
>>
>>been.
>>
>>--
>>Ken
>>http://grundey.blogspot.com
>>
>>"Gil Tellier" wrote in message
>>news:4568dac1\$1@bbsnotes.ugs.com...
>>>
>>> In practicing dimensioning, measurements were made for the length of a
>>> pulley
>>> belt located on 2 and 4 inch diameters with centerlines 4 inches apart.

>>
>>> Using
>>> ZOOM and math analysis, it was found that small position errors could
>>> result
>>> unless features were locked. Question is what constitutes locked? The
>>> included
>>> file shows initial two attempts with errors followed by a successful
>>> third
>>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>>> investigates
>>> why but only serves to raise the question shown. The angle error
>>> indicated

>>
>>> is
>>> nearly 3% and is unacceptable. How can the line be tangent without being
>>> perpendicular? Is there error in the program or the drawing shown? How
>>> can

>>
>>> this
>>> error be avoided?

>>
>>
>>
>

# Re: Tangent Angle Error

Not applicable

Ken,
I am about 80% there with the split command. However, I cannot place the 4.0 inch
between centers nor obtain a verticle dim line through the hole center and radial
line through the split points. See sheet 2 of attachment.
Gil

"PellaKen" wrote:
>Gil,
> I started with two circles set at the radiuses shown, I placed a
>Horizontal Connect between the two centers, added the tangent lines on the
>
>side which received both an Point On Connect (the "X") and a Tangent
>constraint on each end. To be able to measure the arc length on each
>circle, I used the Split Element command to split the circles into arcs at
>
>the endpoint of the lines.
>
>
>The angle dimensions where placed using the Horizontal/Vertical option and
>
>selecting the center point of the circle and the endpoint of the line (very
>
>important to select the keypoints on the element and not the element in
>general).
>
>--
>Ken
>http://grundey.blogspot.com
>
>"Gil Tellier" wrote in message
>news:456a8eac@bbsnotes.ugs.com...
>>
>> Ken,
>> Thanks for the sketch. I have attempted to duplicate your results: draw

>
>> two circles
>> and tangent lines, trim two inner arcs, dim tangent line and arc lengths,

>
>> arcs back concentric, with the results shown in the attachment. I could

>
>> not produce
>> green vertical dim line to get tangent angles and 4.00 dims. I also noted

>
>> a missing
>> Point on (whatever that is) and an X at the connect points that was on
>> Last, your radial dims seem locked and can be duplicated but not moved.

>
>> Thanks again
>> for the help.
>> Gil Tellier
>>
>> "PellaKen" wrote:
>>>I looked at your sketches, and essentially all could be fixed by properly
>>>
>>>constraining the geometry. I have attached what was your "second try" and
>>>
>>>cleaned it up and simplified it. It is not necessary to use all the
>>>construction geometry. Some of your problems were caused by geometry
>>>overlaid on other geometry which was not connected to what it should have
>>>
>>>been.
>>>
>>>--
>>>Ken
>>>http://grundey.blogspot.com
>>>
>>>"Gil Tellier" wrote in message
>>>news:4568dac1\$1@bbsnotes.ugs.com...
>>>>
>>>> In practicing dimensioning, measurements were made for the length of a
>>>> pulley
>>>> belt located on 2 and 4 inch diameters with centerlines 4 inches apart.
>>>
>>>> Using
>>>> ZOOM and math analysis, it was found that small position errors could
>>>> result
>>>> unless features were locked. Question is what constitutes locked? The
>>>> included
>>>> file shows initial two attempts with errors followed by a successful
>>>> third
>>>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>>>> investigates
>>>> why but only serves to raise the question shown. The angle error
>>>> indicated
>>>
>>>> is
>>>> nearly 3% and is unacceptable. How can the line be tangent without being
>>>> perpendicular? Is there error in the program or the drawing shown? How

>
>>>> can
>>>
>>>> this
>>>> error be avoided?
>>>
>>>
>>>

>>
>
>

# Re: Tangent Angle Error

Not applicable

Ken,
After playing aroung with your file, reading the help files to no avail, I stumbled
on the answers to my two questions: (1)to place a 4.0 dim between two circles on
a horizontal grid line, use SmartDim with the hor/vert option and click on each
circle perimeter, not the center (the same result can be obtained using DistBetween
with 2 point option except that the circle must light up and the center mark be
visible on each with the mouse click); and, (2)to obtain a vertical angular dim
line through a circle center, use Angle Between and pass the cursor over the circle
causing it to light up red, click on the center then the line tangent point. For
the gurus, did I miss this in the instruction manual? Thanks again for your help
Ken. I have attached my practice file for others.
Gil Tellier
"Gil Tellier" wrote:
>
>
>
>Ken,
>I am about 80% there with the split command. However, I cannot place the 4.0
>inch
>between centers nor obtain a verticle dim line through the hole center and
>line through the split points. See sheet 2 of attachment.
>Gil
>
>
>"PellaKen" wrote:
>>Gil,
>> I started with two circles set at the radiuses shown, I placed a
>>Horizontal Connect between the two centers, added the tangent lines on the
>>
>>side which received both an Point On Connect (the "X") and a Tangent
>>constraint on each end. To be able to measure the arc length on each
>>circle, I used the Split Element command to split the circles into arcs at
>>
>>the endpoint of the lines.
>>
>>
>>The angle dimensions where placed using the Horizontal/Vertical option and
>>
>>selecting the center point of the circle and the endpoint of the line (very
>>
>>important to select the keypoints on the element and not the element in
>>general).
>>
>>--
>>Ken
>>http://grundey.blogspot.com
>>
>>"Gil Tellier" wrote in message
>>news:456a8eac@bbsnotes.ugs.com...
>>>
>>> Ken,
>>> Thanks for the sketch. I have attempted to duplicate your results: draw

>>
>>> two circles
>>> and tangent lines, trim two inner arcs, dim tangent line and arc lengths,

>>
>>> arcs back concentric, with the results shown in the attachment. I could

>>
>>> not produce
>>> green vertical dim line to get tangent angles and 4.00 dims. I also noted

>>
>>> a missing
>>> Point on (whatever that is) and an X at the connect points that was on

>
>>> Last, your radial dims seem locked and can be duplicated but not moved.

>>
>>> Thanks again
>>> for the help.
>>> Gil Tellier
>>>
>>> "PellaKen" wrote:
>>>>I looked at your sketches, and essentially all could be fixed by properly
>>>>
>>>>constraining the geometry. I have attached what was your "second try"

>and
>>>>
>>>>cleaned it up and simplified it. It is not necessary to use all the
>>>>construction geometry. Some of your problems were caused by geometry
>>>>overlaid on other geometry which was not connected to what it should have
>>>>
>>>>been.
>>>>
>>>>--
>>>>Ken
>>>>http://grundey.blogspot.com
>>>>
>>>>"Gil Tellier" wrote in message
>>>>news:4568dac1\$1@bbsnotes.ugs.com...
>>>>>
>>>>> In practicing dimensioning, measurements were made for the length of

>a
>>>>> pulley
>>>>> belt located on 2 and 4 inch diameters with centerlines 4 inches apart.
>>>>
>>>>> Using
>>>>> ZOOM and math analysis, it was found that small position errors could
>>>>> result
>>>>> unless features were locked. Question is what constitutes locked? The
>>>>> included
>>>>> file shows initial two attempts with errors followed by a successful

>
>>>>> third
>>>>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>>>>> investigates
>>>>> why but only serves to raise the question shown. The angle error
>>>>> indicated
>>>>
>>>>> is
>>>>> nearly 3% and is unacceptable. How can the line be tangent without being
>>>>> perpendicular? Is there error in the program or the drawing shown? How

>>
>>>>> can
>>>>
>>>>> this
>>>>> error be avoided?
>>>>
>>>>
>>>>
>>>

>>
>>
>

# Re: Tangent Angle Error

Not applicable
I don't know that you missed anything (It is probably not documented or is
buried somewhere where it is impossible to find). Just remember that
dimensions behave completely different depending on whether an elements
keypoint is selected as opposed to the element itself and/or based on the
orientation setting (Horiz./Vert. or By Two Points) especially with commands
such as with the Angle Between.
--
Ken
http://grundey.blogspot.com
"Gil Tellier" wrote in message
news:456cde70@bbsnotes.ugs.com...
>
> Ken,
> After playing aroung with your file, reading the help files to no avail, I
> stumbled
> on the answers to my two questions: (1)to place a 4.0 dim between two
> circles on
> a horizontal grid line, use SmartDim with the hor/vert option and click on
> each
> circle perimeter, not the center (the same result can be obtained using
> DistBetween
> with 2 point option except that the circle must light up and the center
> mark be
> visible on each with the mouse click); and, (2)to obtain a vertical
> angular dim
> line through a circle center, use Angle Between and pass the cursor over
> the circle
> causing it to light up red, click on the center then the line tangent
> point. For
> the gurus, did I miss this in the instruction manual? Thanks again for
> Ken. I have attached my practice file for others.
> Gil Tellier
>
> "Gil Tellier" wrote:
>>
>>
>>
>>Ken,
>>I am about 80% there with the split command. However, I cannot place the
>>4.0
>>inch
>>between centers nor obtain a verticle dim line through the hole center and
>>line through the split points. See sheet 2 of attachment.
>>Gil
>>
>>
>>"PellaKen" wrote:
>>>Gil,
>>> I started with two circles set at the radiuses shown, I placed a
>>>Horizontal Connect between the two centers, added the tangent lines on
>>>the
>>>
>>>side which received both an Point On Connect (the "X") and a Tangent
>>>constraint on each end. To be able to measure the arc length on each
>>>circle, I used the Split Element command to split the circles into arcs
>>>at
>>>
>>>the endpoint of the lines.
>>>
>>>
>>>The angle dimensions where placed using the Horizontal/Vertical option
>>>and
>>>
>>>selecting the center point of the circle and the endpoint of the line
>>>(very
>>>
>>>important to select the keypoints on the element and not the element in
>>>general).
>>>
>>>--
>>>Ken
>>>http://grundey.blogspot.com
>>>
>>>"Gil Tellier" wrote in message
>>>news:456a8eac@bbsnotes.ugs.com...
>>>>
>>>> Ken,
>>>> Thanks for the sketch. I have attempted to duplicate your results: draw
>>>
>>>> two circles
>>>> and tangent lines, trim two inner arcs, dim tangent line and arc
>>>> lengths,
>>>
>>>> arcs back concentric, with the results shown in the attachment. I could
>>>
>>>> not produce
>>>> green vertical dim line to get tangent angles and 4.00 dims. I also
>>>> noted
>>>
>>>> a missing
>>>> Point on (whatever that is) and an X at the connect points that was on

>>
>>>> Last, your radial dims seem locked and can be duplicated but not moved.
>>>
>>>> Thanks again
>>>> for the help.
>>>> Gil Tellier
>>>>
>>>> "PellaKen" wrote:
>>>>>I looked at your sketches, and essentially all could be fixed by
>>>>>properly
>>>>>
>>>>>constraining the geometry. I have attached what was your "second try"

>>and
>>>>>
>>>>>cleaned it up and simplified it. It is not necessary to use all the
>>>>>construction geometry. Some of your problems were caused by geometry
>>>>>overlaid on other geometry which was not connected to what it should
>>>>>have
>>>>>
>>>>>been.
>>>>>
>>>>>--
>>>>>Ken
>>>>>http://grundey.blogspot.com
>>>>>
>>>>>"Gil Tellier" wrote in message
>>>>>news:4568dac1\$1@bbsnotes.ugs.com...
>>>>>>
>>>>>> In practicing dimensioning, measurements were made for the length of

>>a
>>>>>> pulley
>>>>>> belt located on 2 and 4 inch diameters with centerlines 4 inches
>>>>>> apart.
>>>>>
>>>>>> Using
>>>>>> ZOOM and math analysis, it was found that small position errors could
>>>>>> result
>>>>>> unless features were locked. Question is what constitutes locked? The
>>>>>> included
>>>>>> file shows initial two attempts with errors followed by a successful

>>
>>>>>> third
>>>>>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>>>>>> investigates
>>>>>> why but only serves to raise the question shown. The angle error
>>>>>> indicated
>>>>>
>>>>>> is
>>>>>> nearly 3% and is unacceptable. How can the line be tangent without
>>>>>> being
>>>>>> perpendicular? Is there error in the program or the drawing shown?
>>>>>> How
>>>
>>>>>> can
>>>>>
>>>>>> this
>>>>>> error be avoided?
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>

>>
>

# Re: Tangent Angle Error

Not applicable

Ken,
Good points that I'll keep in mind. I think that this concludes our session
so thanks again for the assist.
Gil Tellier
"PellaKen" wrote:
>I don't know that you missed anything (It is probably not documented or is
>
>buried somewhere where it is impossible to find). Just remember that
>dimensions behave completely different depending on whether an elements
>keypoint is selected as opposed to the element itself and/or based on the
>
>orientation setting (Horiz./Vert. or By Two Points) especially with commands
>
>such as with the Angle Between.
>
>--
>Ken
>http://grundey.blogspot.com
>
>"Gil Tellier" wrote in message
>news:456cde70@bbsnotes.ugs.com...
>>
>> Ken,
>> After playing aroung with your file, reading the help files to no avail,

>I
>> stumbled
>> on the answers to my two questions: (1)to place a 4.0 dim between two
>> circles on
>> a horizontal grid line, use SmartDim with the hor/vert option and click

>on
>> each
>> circle perimeter, not the center (the same result can be obtained using

>
>> DistBetween
>> with 2 point option except that the circle must light up and the center

>
>> mark be
>> visible on each with the mouse click); and, (2)to obtain a vertical
>> angular dim
>> line through a circle center, use Angle Between and pass the cursor over

>
>> the circle
>> causing it to light up red, click on the center then the line tangent
>> point. For
>> the gurus, did I miss this in the instruction manual? Thanks again for
>> Ken. I have attached my practice file for others.
>> Gil Tellier
>>
>> "Gil Tellier" wrote:
>>>
>>>
>>>
>>>Ken,
>>>I am about 80% there with the split command. However, I cannot place the

>
>>>4.0
>>>inch
>>>between centers nor obtain a verticle dim line through the hole center and
>>>line through the split points. See sheet 2 of attachment.
>>>Gil
>>>
>>>
>>>"PellaKen" wrote:
>>>>Gil,
>>>> I started with two circles set at the radiuses shown, I placed a
>>>>Horizontal Connect between the two centers, added the tangent lines on

>
>>>>the
>>>>
>>>>side which received both an Point On Connect (the "X") and a Tangent
>>>>constraint on each end. To be able to measure the arc length on each
>>>>circle, I used the Split Element command to split the circles into arcs

>
>>>>at
>>>>
>>>>the endpoint of the lines.
>>>>
>>>>
>>>>The angle dimensions where placed using the Horizontal/Vertical option

>
>>>>and
>>>>
>>>>selecting the center point of the circle and the endpoint of the line
>>>>(very
>>>>
>>>>important to select the keypoints on the element and not the element in
>>>>general).
>>>>
>>>>--
>>>>Ken
>>>>http://grundey.blogspot.com
>>>>
>>>>"Gil Tellier" wrote in message
>>>>news:456a8eac@bbsnotes.ugs.com...
>>>>>
>>>>> Ken,
>>>>> Thanks for the sketch. I have attempted to duplicate your results: draw
>>>>
>>>>> two circles
>>>>> and tangent lines, trim two inner arcs, dim tangent line and arc
>>>>> lengths,
>>>>
>>>>> arcs back concentric, with the results shown in the attachment. I could
>>>>
>>>>> not produce
>>>>> green vertical dim line to get tangent angles and 4.00 dims. I also
>>>>> noted
>>>>
>>>>> a missing
>>>>> Point on (whatever that is) and an X at the connect points that was on
>>>
>>>>> Last, your radial dims seem locked and can be duplicated but not moved.
>>>>
>>>>> Thanks again
>>>>> for the help.
>>>>> Gil Tellier
>>>>>
>>>>> "PellaKen" wrote:
>>>>>>I looked at your sketches, and essentially all could be fixed by
>>>>>>properly
>>>>>>
>>>>>>constraining the geometry. I have attached what was your "second try"
>>>and
>>>>>>
>>>>>>cleaned it up and simplified it. It is not necessary to use all the
>>>>>>construction geometry. Some of your problems were caused by geometry
>>>>>>overlaid on other geometry which was not connected to what it should

>
>>>>>>have
>>>>>>
>>>>>>been.
>>>>>>
>>>>>>--
>>>>>>Ken
>>>>>>http://grundey.blogspot.com
>>>>>>
>>>>>>"Gil Tellier" wrote in message
>>>>>>news:4568dac1\$1@bbsnotes.ugs.com...
>>>>>>>
>>>>>>> In practicing dimensioning, measurements were made for the length of
>>>a
>>>>>>> pulley
>>>>>>> belt located on 2 and 4 inch diameters with centerlines 4 inches
>>>>>>> apart.
>>>>>>
>>>>>>> Using
>>>>>>> ZOOM and math analysis, it was found that small position errors could
>>>>>>> result
>>>>>>> unless features were locked. Question is what constitutes locked? The
>>>>>>> included
>>>>>>> file shows initial two attempts with errors followed by a successful
>>>
>>>>>>> third
>>>>>>> attempt agreeing with Excel analysis to 7 figures. The fourth sheet
>>>>>>> investigates
>>>>>>> why but only serves to raise the question shown. The angle error
>>>>>>> indicated
>>>>>>
>>>>>>> is
>>>>>>> nearly 3% and is unacceptable. How can the line be tangent without

>
>>>>>>> being
>>>>>>> perpendicular? Is there error in the program or the drawing shown?

>
>>>>>>> How
>>>>
>>>>>>> can
>>>>>>
>>>>>>> this
>>>>>>> error be avoided?
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>

>>
>
>