Integration along a line

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 July 20, 2011, 08:19 Integration along a line #1 New Member   Dijun Pan Join Date: Jun 2011 Posts: 13 Rep Power: 8 Sponsored Links Hi all friends, I have a problem which required the Z coordinate at a polyline and integrate it with respected to x . eg. Z^2dx How can I create variable which gives me the Z^2 value at the polyline? Thank you in advance Dijun

 July 20, 2011, 19:24 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,735 Rep Power: 106 Two ideas: 1) Generate a user variable defined as z^2, and integrate that alone the polyline. 2) use a CEL expression like lineInt(z^2)@polyline and calculate it directly. This can be done in the table view.

July 21, 2011, 06:01
#3
New Member

Dijun Pan
Join Date: Jun 2011
Posts: 13
Rep Power: 8
Quote:
 Originally Posted by ghorrocks Two ideas: 1) Generate a user variable defined as z^2, and integrate that alone the polyline. 2) use a CEL expression like lineInt(z^2)@polyline and calculate it directly. This can be done in the table view.
Hi， Ghorrocks，

But if I use lengthInt()@Polyline 1, the result will be the integration with respected to polyline. I try to use the z^2 in the polyline but integrate it with respected to x.

Regards

Dijun

 July 21, 2011, 08:13 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 13,735 Rep Power: 106 I see. You might be able to transform the integral into a with respect to length (dl) integral using a chain rule or something like that. Been so long since I have done that sort of stuff I can't remember off the top of my head. Otherwise export the points of your polyline including XYZ values of the points and then you can do the integration in another package like excel, tecplot or matlab.

July 22, 2011, 14:12
#5
New Member

Dijun Pan
Join Date: Jun 2011
Posts: 13
Rep Power: 8
Quote:
 Originally Posted by ghorrocks I see. You might be able to transform the integral into a with respect to length (dl) integral using a chain rule or something like that. Been so long since I have done that sort of stuff I can't remember off the top of my head. Otherwise export the points of your polyline including XYZ values of the points and then you can do the integration in another package like excel, tecplot or matlab.
Thank you very much! I didn't figure out the way you said but I did the integration by using areaInt_z at the surface then divided by the width of the surface

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