Author Topic: ( C3D ) Accumulation errors  (Read 5531 times)

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DinØsaur

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Re: ( C3D ) Accumulation errors
« Reply #30 on: August 03, 2007, 02:27:47 pm »
But Randy,  this is municipal review staff we are tying to get past to have a project approved to join the public infrastructure.  The dirty little secret is that sometimes the city or county does not really want something built there yet because some facet of city service won't be adequate to absorb the new development.  Regardless, the project can not go forward until each reviewer involved is convinced all of the information is complete and correct by whatever criteria they are using.  The only control we can exert is send the client to someone's boss to get the bearings lubricated.  If the client has enough clout it even works on occasion.
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CADaver

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Re: ( C3D ) Accumulation errors
« Reply #31 on: August 03, 2007, 02:35:49 pm »
But Randy,  this is municipal review staff we are tying to get past to have a project approved to join the public infrastructure.  The dirty little secret is that sometimes the city or county does not really want something built there yet because some facet of city service won't be adequate to absorb the new development.  Regardless, the project can not go forward until each reviewer involved is convinced all of the information is complete and correct by whatever criteria they are using.  The only control we can exert is send the client to someone's boss to get the bearings lubricated.  If the client has enough clout it even works on occasion.
Oh I quite understand that.  Such is not a problem with the tool however.  We're back to the stick. 

Rounding discrepancies (not errors) are the primary reason I’ll never dual dimension Imperial/Metric on a drawing.  Everything on the drawing is quite accurate, but rounding pushes some dimension a millimeter or a sixteenth one way or the other, and some bozo checker somewhere “knee-jerks” into slobbering hysteria.  “Bozo, meet stick.”  My, that is a pleasant “ring” isn’t it?

Mark

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Re: ( C3D ) Accumulation errors
« Reply #32 on: August 03, 2007, 03:02:33 pm »
Quote
Then using those tools we work very hard producing an accurate representation.
WRONG! ( http://www.theswamp.org/screens/mark/screen_shots/stations.png ) isn't an accurate representation.
.....
In my case it IS accuracy. If the numbers don't add up then there is SOMETHING wrong with the drawing.
There is rounding going on there (rounding is not inaccurate, its just rounding). Run all the numbers out to eight decimal places.
If I show a inverse distance between two stations and it doesn't match the station distance then it is not accurate. Why does C3D ( the "tool" ) do that? It's labeling the stations AND the inverse distance of that segment!
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CADaver

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Re: ( C3D ) Accumulation errors
« Reply #33 on: August 03, 2007, 03:32:10 pm »
Quote
Then using those tools we work very hard producing an accurate representation.
WRONG! ( http://www.theswamp.org/screens/mark/screen_shots/stations.png ) isn't an accurate representation.
.....
In my case it IS accuracy. If the numbers don't add up then there is SOMETHING wrong with the drawing.
There is rounding going on there (rounding is not inaccurate, its just rounding). Run all the numbers out to eight decimal places.
If I show a inverse distance between two stations and it doesn't match the station distance then it is not accurate.
It is quite accurate within the parameters you've set, 2 decimal places.

Jeff_M

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Re: ( C3D ) Accumulation errors
« Reply #34 on: August 03, 2007, 03:45:53 pm »
It's labeling the stations AND the inverse distance of that segment!
No, it's labeling the stations based on the position of the labeled points along the alignment in relation to the beginning station of the alignment. The labeled segment is just that, a segment whose length is not governed by the total length, but is a part of the overall length.

This is something that has boggled many minds when working in the City I mainly work in. The guys checking the Road plans seem to have a grasp on reality and have never questioned the Station Difference vs segment length. Possibly because we supply them with centerline calcs output to 3 decimal places, including the stations, and they can see for themselves that it is a rounding issue. I just wish they'd talk to the guys doing the map checking, because they don't have a clue.....

jpostlewait

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Re: ( C3D ) Accumulation errors
« Reply #35 on: August 03, 2007, 10:10:56 pm »
I'll try tomorrow Dino. I had to explode the stations and renumber them to get it out the door today.

So you are done and you move on.
If you think it's nuts to sit around and argue about hundredths of a foot with an idiot, take him out to the job site and tell him you set one hub a hundredth incorrectly and ask him to point it out.
For a guy how grew up in the field the inane math requirements placed upon plan documents either civil or building is crazy.
One of our DOT's requires that all Math be precise at two decimal places. So you just construct everything to exactly 2 decimal place distances.
All slopes are evenly divisible by 4.
I know why this made sense 40 years ago.
Some rates of change are slower than others.