Blend between two circles in different elevation

[Purus_Cdds]

I am trying to blend between two circles. but the blend curve is not straight as i marked. Why not?

Your help is appreciated.

[barthbradley]

A blend doesn't work that way. It only has two opposing profiles.  You need to loft it.  Mass environment.  

...or use 2 blends; stacked. 

[ramabalanv]

@Purus_Cdds,

I guess, out of your two circles (profile),  one circle(profile) is splitted. Thats why the blend profile is curvy. If you use circle for two sketches without any split, the path of the blend will be straight.

[barthbradley]

[Purus_Cdds]

That is not the case. i have both circles no (2) arcs.

[Purus_Cdds]

Can you please check the attached rfa file?

[barthbradley]

You used the wrong tool.  Don't use a Blend. Use a Sweep Blend or Revolve. 

...you want it to look like this; right?  Sweep Blend shown. 

[Purus_Cdds]

Please check in front view. I need 9" offset between center to center as shown in the image below.

[barthbradley]

Okay...then use a Blend.  I thought you wanted a conical shape.  You're not going to get a conical shape unless the profiles remain perpendicular to the path.  

[ToanDN · Accepted solution]

Create two halves and join.

[barthbradley]

@Purus_Cdds: So this is the shape you're trying the achieve?  

Elevation View:

[barthbradley]

@Purus_Cdds: I notice the your family is named Catch Basin, and that it's 10'-0" deep.  Is this a manhole?  Is so, may I submit that only one side is tapered; that the other side is parallel to, and in-line with the manhole side wall below it (the side with the ladder steps).   Something like is shown in this picture: 

[Purus_Cdds]

That works..! I am happy with this solution but there must be a different way.

[Purus_Cdds]

Yes! that is a man hole for storm pipes.

[barthbradley]

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@Purus_Cdds wrote:

Yes! that is a man hole for storm pipes.

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Well, I hate to tell you, but is that's your design objective, then your math is off.  Should be a 8" not 9" offset from center with a 3'-6" dia. man opening and a 4'-10" dia throat opening.  With 9", you have a 1 degree taper on the side opposite the major taper.  You want zero taper on that side.  Not knit-picking. Just pointing out a possible design error, that could come back to bite you in the butt.  And, it's all free advice too.  How about that?  

[barthbradley]

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@Purus_Cdds wrote:

That works..! I am happy with this solution but there must be a different way.

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Ha! Yah, @ToanDN; there must be a different way! Can you work on a few more solutions and get those submitted for approval by the 8:00 AM PST? Thanks. You're the best, man.    

[barthbradley]

Hey!!! I figured out how to do the eccentric using a Sweep Blend, and it was pretty fricking easy too! Anybody still interested?  Or, are we done here? 

If so, I'll share the trick with you...

[ToanDN]

You mean this?

[barthbradley]

...maybe. maybe not.

...show me sketch mode for the top profile.

BTW @ToanDN: that's exactly what I showed above (the conical shape uses this approach).   

[ToanDN]