How do I loft this pipe to a different diameter?

How do I loft this pipe to a different diameter?

matthewpolack
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Message 1 of 17

How do I loft this pipe to a different diameter?

matthewpolack
Enthusiast
Enthusiast

Hi,

I'm trying to get a pipe to loft up to a slightly larger diameter for a shop vac..but no matter what I try I can't get it to work? It just give an error "The loft could not be created. Try changing profiles for rails or center line or adjusting continuity conditions." (Which I don't really understand!)

How can I get two different pipe diameters to join? Thanks for any clues!

 

https://a360.co/3bmDe3D

 

matthewpolack_0-1656228879559.png

 

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Accepted solutions (3)
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16 Replies
Replies (16)
Message 2 of 17

davebYYPCU
Consultant
Consultant

Use outside circles for solid loft.

Use inside circles for an inside cut loft.

 

tlft.PNG

You need another sketch on the end of the pipe, or solid pipe and shell after the loft.

Loft can not do donuts in one go.

Message 3 of 17

g-andresen
Consultant
Consultant

Hi,

In solid mode, lofting of hollowed bodies is not possible. In this case, you must project the profile on a sketch on the pipe and then first loft the outer profile and then the inner profile with the CUT option.

 

Screencast

 

günther

 

Message 4 of 17

matthewpolack
Enthusiast
Enthusiast

Thank you I really appreciate the replies...but I'm struggling to get this to work. I'm having difficult getting the loft command to work. I'm doing something wrong. Here is step by step what I try:

 

1) I click on the open end of the pipe..and I create an Offset plane.

2) I click on this plane..and then create a centre circle.

3) I highlight the new circle sketch at the end of the pipe...a completely solid circle.....exit the sketch...then click on the larger circle about 10mm above. Again just a solid circle.

4) I choose "Loft"

5) The loft command does not work as I'm used to...it just doesn't connect. It looks like this picture. Thank you..I really don't understand why this doesn't work?

 

matthewpolack_0-1656241860449.png

 

Edit: I've just discovered if I start a completely new design I can get a loft to work from one circle to another..but inside this particular project the loft feature appears broken! (Or I've somehow destroyed lofting ability!)

 

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Message 5 of 17

matthewpolack
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Enthusiast

Ok..this is absolutely weird...I've just drawn two circles above each other..I choose Loft...and nothing happens..but there is a loft in the timeline. Interestingly there is a centre dot that I don't normally see. Can anyone figure out what is going on? Here is the current project:

 

https://a360.co/3bmDe3D

 

Screenshot of the loft that isn't a loft!

matthewpolack_1-1656243112750.png

 

Edit: I actually just recreated a blank pipe in another file...and this worked well..so something somehow has become corrupted in that main project that blocks lofting! Really strange.

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Message 6 of 17

davebYYPCU
Consultant
Consultant
Accepted solution

Turn off your Section Analysis.

Ask me how I know. (Check my pic, above)

Message 7 of 17

TheCADWhisperer
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Consultant
Accepted solution

@matthewpolack wrote:

...inside this particular project the loft feature appears broken! (Or I've somehow destroyed lofting ability!)


Whenever you get unexpected behavior - you should Attach this new file here.

The geometry is there.

TheCADWhisperer_0-1656245538146.png

 

Tip: Rather than attempting to Loft pipes - model as solid and use Shell instead.

 

BTW - where are your dimensions? Blue sketches should keep you awake at night.

And this could have been done with Revolve rather than Loft.

Message 8 of 17

matthewpolack
Enthusiast
Enthusiast

Thanks so much. I've been working for a couple of hours on trying to get this to work! I ended up trying the strategy mentioned above which was to loft cut...but this wouldn't work to cut! (The "Ok" button is greyed out.) Looks like maybe I should have tried a different strategy like shell or revolve? Thanks so much for the help...I'm really struggling with how to do this...what is the best method...and there is just so much I don't understand...but will keep trying! Thank you.

 

matthewpolack_0-1656246239343.png

 

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Message 9 of 17

matthewpolack
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Enthusiast
Thanks for this...I couldn't figure out how to model as a soilid...I tried a loft to loft...but then it went in a really strange straight line...not a nice curve which I need...which I think might be solved by rails?
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Message 10 of 17

matthewpolack
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Enthusiast

Thanks for this file. I can see what you have done now..thank you!
One last question,..when i do shell command on mine...my shell command does not punch a hole in the bottom like yours? It is left with a base like this?

 

EDIT: I get it now...you make the entire pipe first...THEN shell it later...thank you! That makes sense!

 

matthewpolack_0-1656247151704.png

 

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Message 11 of 17

matthewpolack
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Enthusiast

Well I got there...thank you all...took me several hours...but a lot of that was education in the process! Thank you very much! 

matthewpolack_0-1656247827727.png

 

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Message 12 of 17

davebYYPCU
Consultant
Consultant

In case you are still wondering about message 8, the Ok button is greyed out.  You have not yet selected a second profile.

 

Might help...

 

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Message 13 of 17

matthewpolack
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Enthusiast
Thanks for this.. as I am still confused about this method.. I selected the bottom sketch... Then the top sketch.. but it still wouldn't cut.. when you say 'second profile' . What do you mean? Which specific thing do I click on? Thanks so much.
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Message 14 of 17

davebYYPCU
Consultant
Consultant
Accepted solution

In your pic, message 8 top section of the Dialogue Box, there is only one profile listed, Loft requires 2 or more profiles.  That pic also does not show an internal circle on the pipe face, so selecting the pipe face may not have been accepted.

 

So at that stage you have a solid elbow (not shelled or hollow yet), adding a solid Loft does not need a sketch on the elbow face, but adding a cut Loft does need the internal diameter at the solid face to be identified, and selectable.

 

To save the grief, a solid pipe, then solid Loft joined, then shell both end faces, (preferred and ) is the easiest to understand.

 

However if the article in Message 7 is the end game, then I would do that with hollow sweep, with a Path / Guide rail.

 

Might help....

 

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Message 15 of 17

matthewpolack
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Enthusiast

Thanks for that..;.I thought I actually had two profiles selected with that attempt...did have two sketches...anyway I've learned just to make a solid...and use the shell command...a far easier approach as you said. Will research this "Hollow Sweep" method you mention as that is something I haven't learned about yet. Thank you. Appreciate your time!

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Message 16 of 17

davebYYPCU
Consultant
Consultant

Actually the sweep scales the wall thickness if done with donut profile, so back to Shell.

 

SwpPthGR.PNGSwpPthGR2.PNG

(Modified Whisperer's file for this demo - so pipe and intermediate sketch stuff, are not strictly required.)

Dimensions are required to fully constrain some sketches.

 

Might help....

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Message 17 of 17

matthewpolack
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Enthusiast

Thanks for that...have started watching a video or two on the "Sweep" tool...looks like another great one in the arsenal!

One step at a time am getting more familiar with this software...really is amazing the possibilities. Appreciate the support. Thanks!

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