Over the years I have looked at various ways to produce an eccentric reducer with it's correct profile but have not really found an optimal method yet, here are the methods I have tried so far.

(1)lofting a number of circles that make up the profile
(2)extruding the straight parts at both end and then fitting a frustum of an oblique cone between, boolean adding and then doing a reducing fillet radius on the junctions of the straight ends to the oblique cone frustum intersection.

How would you approach it in Moi to achieve the smooth transition as shown in the images below?.

Would a reducing sweep along a center line path be suitable in Moi?.

I should have added, i am using Moi v2

The reason for finding the best method is this, I will have lots to create over a period of time and also want to look at the best profile and file or block size comparison.

Blend is nice for v3

Command Blend (surface) can help ...



1. Make profile S1, S2, D1 D2, move S2, D2 profile to H
2. Extrude profile for surface blend reference
3. Use command blend (you can delete profile circle's and please select only edges) for blending extruded profile, delete extruded surface's
4. Extrude edge's from inside surface option tapered, (see attached file, object 5)
5. Select new tapered surface's and outside surface, use Boolean --> Merge
6. Remove unwanted surface's and join other

Hi Michael, yes probably as mentioned above Blend between 2 cylinders could work - delete the end caps off the cylinders before you use Blend on the edges.

Also if I understand correctly Loft should work as well, if you use the "Loft style = Loose" option. For using the loose loft, you will want to have 2 duplicates for the first and last profiles. You would arrange them like this:



Then when doing the loft (again, the key thing is setting the option for "Loft style = Loose", not the default mode that forces the loft to go directly through every profile), you will get this kind of result:



- Michael

Both methods have worked well lads.

Michael with a bit of trial and error to get a more square end as it approaches the ends works okay.

Eddi, a bit more work but a nice finished result. I have only used your version as a render as not sure how you have done it yet, is this possible in V2?.

I work primarily with Turbocad, but find that some things are better done in Moi as some of Michael's routines are very flexible plus Turbocad and Moi file interchangeability works spot on.

>> I have only used your version as a render as not sure how you have done it yet, is this possible in V2?

I think easy, try it, if problem occurs, ask for solution.

Regards

Will do Eddi, and thank you for the input!.

EDDI, still trying to figure out how you did it with blend but managed it with sweep.

Hi Michael to use Blend you would need to extrude out the circles, hide the circle curves (so they don't get in the way of selecting edges), and then delete the end caps of the extrusions (or extrude them with "Cap ends" option unchecked) so that you have 2 extrusions with open unjoined edges at their ends. Then you select the edges and run Construct > Blend to build a blend surface between them.

The setup with 2 edges selected (again, note it's _edges_ that must be selected, not the original curves, hide the original curves so you don't select them instead and the edges should not be joined in between 2 surfaces so that's why you delete the end caps) looks like this:



Then when you run Construct > Blend the connecting blend surface will look like this:



- Michael

Got it Michael, I must have been selecting the curves.

Will give it a try!.

Foiled again!

But since I made it, I'll put it here anyway.....

Many thanks lads all has worked well with the different variations, just got to set about finding out which one will produce the smallest acis solid file size in combination with the best profile and then I am on the move.