V5 - Multi-Section Surfaces Area Law Help 1

[VN1981]

Folks,
I need to create a surface loft with area law (change ratio) and I just discovered that V5 offers to accommodate such a law during lofting. I went through the help and tried following similar procedure to my sections and Catia is giving me error. The help manual is not comprehensive as in it does not give out limitations and I wish they had included a few more complex sections examples as well.

Posting screenshots of my sections in hope that people with experience of incorporating area law will be able to identify my mistakes and help me correct it. Just want to clarify that the below is a test case but the final surface should be similar.

I have 3 sections...the first section is an ellipse, the middle one is a circle & final one is a rounded square. The distance between the first & last section is 300mm.

Front view of all 3 sections:

In the Dassualt supplied example, the distance between the curve/spline points (at each section) and the reference line is equal to the radius of the sections. So my thought process was, for sections other than circular, calculate the area of the section and determine an equivalent radius, which is what I have done above.

Reference Line & Law curve in a sketch...similar to what is shown in catia supplied example:

Then extract the curve & horizontal line separately and create a law.

Finally, create a multi-section using area law to get the following error:

I am not sure what I am doing wrong above. Any pointers would be appreciated.

Thanks...

 

[itsmyjob]

This will not solve your LAW problem but:

you have 2 vertices on the ellipse, 8 on the rounded square (i'm guessing here) , then 2 on the circle, you might need to give some help to CATIA so it will know how to match those vertices, check the coupling option (on the online doc or on this forum).

(Guide curves might not be an option as you want to control the section area)

Hope this help

Eric N.
indocti discant et ament meminisse periti ​

 

[rickyt]

First, I think your areas are wrong.
Per your values the rounded square is 20 times larger than your ellipse.
If you get the radius values close and it still is wrong on your preview it will show a deviation value at your sections in red.
Hover over the value, and the equiv radius value will be shown.
Modify your sketch to have all corresponding section values match.
And per what Eric Mentioned, you may need to play with the coupling.

 

[VN1981]

Rickyt,
Wow...it seems like you got it working. Awesome...I got the areas for the sections from Catia it self and I suspect that areas were too small and Catia rounded it off. Thanks for making the observation about areas values being off. Somehow I missed it...duh!

Also Eric, I will be addressing the coupling after I get it Area Law working.

Thanks a lot folks for your replies. Really appreciate the help.

 

[VN1981]

Rickyt,
Thanks a lot for your reply and suggestions.

I was able to get the Multi-Section with Area Law working.