extracting the equation for a curve

[SW]

Is there any way I can extract the equation out of a sketched curve? I want to use the curve equation for integration calculation, preferably within Pro/E.



Thanks,



Sam

 

[magi]

i know there is a possibility for vice versa but iam not sure of the question u ask .cant u create points and create a curve through points u can control the points then externally..





magi

 

[SW]

I have created a blended surface and taken a cross-section through the feature. I then want to use the equation of this curve for an integration calculation. I might be able to use the area under the curve from the massprops information, but it may be difficult to translate the equation. Assuming I can't do this I was hoping to extract the equation that Pro/E is using to define the curve.



As curve is from a surface constructed by b-splines, shouldn't the cross-section curve also have an equation which I can extract?



Thanks,



Sam

 

[Brian_Adkins]

Your best bet may be to pattern points along the curve and then export those points to a CSV file... Then use some curve-fitting software to give you an equation.



-Brian Adkins

 

[Brian_Adkins]

See this thread for extracting point information from a model:



http://www.proecentral.com/portal/forum/msgDetail.asp?msg_id=2702&for_id=15



-Brian Adkins

 

[SW]

Thanks for the help, can you you suggest any suitable (and hopefully free) curve fitting software? I might be able to get Mathcad to do it but I was wondering what else people use.

 

[gkc]

A little help is just to use Excel. You can both blot curves, make curve fitting and extract their equations.

 

[Nose Bleed]

I've used this - it's free...



http://mi.eng.cam.ac.uk/~gmt11/software/eqnsurf/eqnsurf.html

 

[kvision]

There may be an easy way to get your final answer without knowing the equation. What information, exactly, do you want. You may be able to set up a datum analysis feature or User Defined Analysis to generate your answer directly from the geometry using BMX.

 

[Nose Bleed]

I too would like to be able to use Pro/E exclusively for this...



I get my surfaces from scanned cartesian points (CMM). to be able to find out the equation that made that scanned surface, would be of utmost reverse engineering power to me!!



There's got to be a way - without using 3rd party software...

 

[eddie]

Brian, How do I export points to a CSV file?

 

[Brian_Adkins]

eddie,



see previous thread:

http://www.proecentral.com/portal/forum/msgDetail.asp?msg_id=2702&for_id=15



The batch file there will extract point data out of an iges file and convert it into a *.ibl file that you can read into Pro/E as points. It doesn't matter if the iges files also contains surfaces, lines, etc... it should just grab the points.



-Brian Adkins