Topic: I know it can be done !!!

[kpo101]

What I would like to do is (example) Take a cylinder 2" dia. x 18" long  How do manipulate it by means of Turning it into a pipe with 1/8" walls, Flare one end and maybe hour-glass the middle? I've seen this done on a tutorial, but it(the tutorial) didn't have sound. In this tutorial i seen them add a grid to the item then divide the grid into 3 parts and be able to manipulate each of the parts. Any help would be greatly appreciated :loco:. 

[JCTER]

Your best bet is to draw one half of the section - as cut through the LENGTH of the pipe, not the cross section, and then REVOLVE that around the pipe axis.

Better yet, your -best- bet, imo, is to create the pipe using a different OBJECT for each feature.  Even if it's welded pipe, they're all separate off-the-shelf items, whether it's the flanged connections, reducers, velocity stacks, or whatever.

Look at the REVOLVE command in the help file, it should reveal all.

[Matt__W]

Your best bet is to draw one half of the section - as cut through the LENGTH of the pipe, not the cross section, and then REVOLVE that around the pipe axis.

+1

[mjfarrell]

loft then shell

[Matt__W]

Build a surface in C3D!   

[kpo101]

Thank for the REVOLVE lessons guys, it helped out a lot.

[Mark]

Look at the REVOLVE command in the help file, it should reveal all.

That is cool, thanks for that. I'll most likely never use this at work but its good to know.

[JCTER]

One little tip I have picked up though.

If you have a LOFT-ed solid... the CROSS SECTIONS you draw to create this lofted solid will still remain with grips intact.

Say you loft a big circle into a small circle to simulate an eccentric reducer, or something.  You know how with 2D circles you can click the grip and drag it out to make a bigger circle?  You can do that in 3D too, with a lofted solid.  You still retain a lot of grip-control over the solid if you create it right ahead of time.

However, once you SHELL that solid, to create a pipe from it, it may lose that ability.  Personally I don't bother creating hollow pipes.  All out pipes are actually solid cylinders.  We're not a mech/piping/process firm though, so don't take me at my word that our/my method is industry-standard or "right"

[mjfarrell]

I :love: Lofting

Quote from: James Cannon on January 20, 2011, 02:25:34 pm
Your best bet is to draw one half of the section - as cut through the LENGTH of the pipe, not the END section, and then REVOLVE that around the pipe axis.

above should read

with lofting one draws the end sections, and they get strung out along a path

[JCTER]

Yea, REVOLVE is a bit outdated, but I find it's better if you draw the pipes in pieces, since you can still use grip edits on the revolve'd section geometry.  It's also a more intuitive and fail-safe process because there's absolutely no way to NOT be concentric about the pipe axis.  Concentricity is the first feature of importance, rather than absolute diameter, for the most part, in what we do.  So using a method that fixes concentricity in a fail-safe way is more logical, to me.  And with piping, there's nothing that's not circular in cross section, so there's not terribly much benefit to Loft.

Additionally, with loft, there's no -good- way to take a hard 90d turn in your profile.  You can't have two cross sections be co-planar, I mean.  You'd have to have one nudged further along the loft path by 0.001" or something, and I just hate "faking" features like that.  It's no -real- issue, I just hate 'tricking' Autocad into doing things right.

[mjfarrell]

I :love: Lofting

Quote from: James Cannon on January 20, 2011, 02:25:34 pm
Your best bet is to draw one half of the section - as cut through the LENGTH of the pipe, not the END section, and then REVOLVE that around the pipe axis.

above should read

with lofting one draws the end sections, and they get strung out along a path

[JCTER]

...wut?

[Mark]

Wow, lofting is cool too!!

[Lin-Z]

You can also IMPRINT the cylinder with circles/lines at the change points and then use the Ctrl+ face and edge editing options to pull and push the object into the shape you want.  Then SHELL it to the thickness you need.

[dgorsman]

We're not a mech/piping/process firm though, so don't take me at my word that our/my method is industry-standard or "right"

With broad standardization of wall thicknesses, dimensions, and materials for the piping industry there isn't much need to model the interior of piping except for companies doing FEA to validate their parts against code.  You would think that it might have an application in process analysis but they use much simpler software models so the math doesn't get too horrendous.