Rib creation

Hello,

I am a new user, unfamiliar with the Rib command. I have been experimenting with it on a revolved extrusion that has been shelled to form a simple bowl shape - with no success.

I have tried drawing a line centered on the datum axis, and telling the rib to form to the right or to the left, and also by drawing a line on the top plane, and telling the rib to form down, into the bowl. Neither case gets me a feature.

A: What am I doing wrong,

and

B: Do people use Rib, or generally make a normal extrustion using a sketch?

Thanks,

Lynne

I have never used rib. I use either a regular or thin protrusion using the intended upper surface of the rib(create a datum plane specifically for this, because clients change their minds often) and extrude down to the part (thru next). Sometimes you will have to use blind depth instead of thru next and overbuild, then copy the intersecting surface and use it to trim the protrusion where it meets the part.

Mike

i'm constantly using ribs.



they are a life saver, especially patterened.



there's a trick to making them work properly. once you get it, you'll never thin again!



fred

And that trick is..... ?

A rib is always both sides and is always an open section.

The section you sketch must be closed when you consider the geometry it is attatched to. So using the sketch entities and the geometry as bounds it should appear closed.

An extrusion will not always give you the same shape as a rib.

here is the rib sketch

http://www.kinetivision.com/requests/rib_sketch.gif

and here is the finished rib patterned.

http://www.kinetivision.com/requests/rib_fin.gif

The caveat is the top horizontal line of the sketch can't be tangent to the bowl.

the way i create ribs:



1. create a surface copy of the intereior surface the rib will be residing in.



2. create a datum plane as center of the first rib.



3. create a datum curve intersecting the datum plane and the surface copy.



4. create a rib using the datum plane to setup your section, align the open endpoints of you sketched rib profile to the datum curve.



VOILA!



sounds like extra work, BUT, the advantages are overwhelming. especially when the copied surface is complex. good luck patterning across multi-patched surfaces without this method.



PLUS, draft, rounds, etc can then be reference patterned.



grouping symetrical but UN-JOINED ribs helps a lot before patterning too.



clear as rib sauce?



fred

ribs

i al ways follow the procedure as mentioned by kvision and i'm impressed by the way of fhodshon.

thank u

mahesh