Class A to Class B surface generation

[sobzsunny]

Hi friends,

I had some doubts in my mind while working in CATIA V5 in GSD. If I have an A class surface which is not joined and having connexity errors what all steps should I follow to join the surface and then offset it to create the B class surface ( which will have a section profile).

If anyone can share any tutorial or models that I can work on will be of great help

 

[lardman363]

You can join the A surface and increase the tolerance in the join definition window. You can also use heal (hold down the join icon to get to the heal icon) and adjust the tangency and continuity to see if you can get it to stitch (beware, this changes the surface). Maybe try asking for a new surface that has some quality. Most of the time you end up splitting out patches and rebuilding in GSD. Good luck!

 

[sobzsunny]

Thanks for the reply Lardman
So if I have the A-class surface which is having gaps I can also try extrapolating and trimming the surface and then join (depending on the model am working). Do you know about the merging distance, did get this connexity error sometimes ( due to merging I guess).
Any CATIA surfacing tutorials or models to work on.

 

[lardman363]

Merging distance was the tolerance I was referring to in join and heal (heal also gives options for tangency angle). If you try to offset the surface and it gives you a conexity error of 0.02 mm, change your merging distance to that value or greater and see if that fixes it. You could try to extrapolate/split/join but sometimes you have to use fill...which doesnt always offset.

 

[sobzsunny]

Thanks for the comments, understood the problem.

 

[itsmyjob]

gaps in class A surfaces? I had the feeling class A surfaces do have pretty good connections between each other.

Healing will deform the surface, check if you're supposed to do that.

Eric N.
indocti discant et ament meminisse periti ​

 

[sobzsunny]

Ya you are right class A surface have good connections, but this model which I worked was given to me and told to do the surface generation. It had connexity error and there was overlapping also, they were different patches and I had to connect them and create the surface and follow a master section and give thickness at the end. I am not sure if it is A class or just a surface as it was a test I did not get much inputs also.

 

[lardman363]

We get bad "class A" surface all the time...it is nothing new. Either they fix it for us, or we modify it and let them know or parts don't get made.