law without streight line for reference - reverse law+ parallel line process

[Jazzuo]

hello

I would like to ask about reversing a law-parallel process.

in the example i used normal law and parallel process

View attachment 1737

I made white lines
made laws out of white lines
and made vlue lines and green lines

but what if i had only green lines and only the blue middle line to start with, and wanted to make the top and botomn blue line.
how do i make law out of the green lines since it has no straigh one?



thank you

Jazzuo

 

[MrCATIA]

I remember back in CATIA V4, Laws could be made based on Reference geometry of a line, curve, or even a surface. But it seems that with V5, the reference can only be a line. The online Help describes only using a line for the reference.

So, I don't think there is a direct way to make a Law based on the distance between two curves, such as the two green curves in your example.

 

[Jazzuo]

what about indirect ways?

 

[MrCATIA]

One method that I'd try: develop flat patterns (unfold) of the two green curves and add a straight reference line. The distance between the two green curves can be determined by the difference of the distances between the reference and the unfolded curves.
View attachment 1747

1. make a flat surface between the two green curves
2. unfold the surface into a plane, and unfold both green curves
3. draw a line in the plane somewhat parallel to the unfolded lines (this will be the reference line)
4. make two Laws: Law1(D2) between the reference line and the first unfolded line, Law2(D1) between the reference line and second unfolded line
5. add a parallel curve from the blue line using Law1
6. add a second parallel curve, in the opposite direction, from the first parallel line using Law2. This should be the curve you're looking for.

 

[Jazzuo]

Hi i understand what you are trying to say, but i am unable to do it in catia
by step num 2 i just get a surface turned 90 degree not a straigthen out worm

J