Oloid

[Anonymous]

Did someone of you ever model an oloid? I spent a lot of time but can't find
a solution.

Juergen

[-niels-]

The latter 😉

Though i also don't understand why stitching would give different results... maybe someone at AD can answer that one...

[Anonymous]

My best start for modelling an oloid is the sketch in the attached file
"oloid_sketch.ipt". Unfortunately I can't do a loft from sketch1 to sketch2.
Why not - can someone explain? But surprisingly: after deleting the
constuction lines and moving the endpoint of the arcs very very little - the
lofting works and I can complete the oloid (mirror the lofted surfaces and
stich them all, see "oloid_not_exact.ipt"). But the result is not really
good. A zebra analysis shows a curve discontinuity along the line. A good
oloid must look like shown in file "oloid.gif" (attached).

Juergen

[Anonymous]

Oops, a crippled posting.
Here again:
My best start for modelling an oloid is the sketch in the attached file
"oloid_sketch.ipt". Unfortunately I can't do a loft from sketch1 to sketch2
(and don't know why). But If I delete the construction lines and move the
endpoints of the arcs very very little, surprisingly the loft is successful
and I can complete the model ("oloid_not_exact.ipt"). But the zebra analysis
shows me, that this oloid isn't correct, because you can see a curve
discontinuity along the line. A correct oloid must look like in the attached
"oloid.gif".

Juergen

[Anonymous]

As a matter of fact, oloids do have a practical use. Oloids are used for
impeller blades in the water treatment facilities. Check out the following
link for more information about oloids.

http://www.oloid.ch/frame.php3?lang=en&nav=pro&content=oloid_typ200

Hope that helps!

"Ray Dyson" wrote in message
news:5386060@discussion.autodesk.com...
Very close indeed, but if you do a Zebra analysis, you see that mine has
generally smoother transitions.
One question, do you see any difference between the sculpt part and just
stitching up the surfaces?
Of course the unanswered, real question is does this have any practical
application or just a fun study?

[Anonymous]

Whoa, I've been designing toys for over 20 years and never saw this before.
It could have made me a fortune. All I have to do now is find some way to
use it.
Off to the drawing boa.....ugh Keyboard.
Thanks Jim,
Ray


"Jim Strenk (AIP R11 SP1)" wrote
in message news:5386920@discussion.autodesk.com...
As a matter of fact, oloids do have a practical use. Oloids are used for
impeller blades in the water treatment facilities. Check out the following
link for more information about oloids.

http://www.oloid.ch/frame.php3?lang=en&nav=pro&content=oloid_typ200

Hope that helps!

"Ray Dyson" wrote in message
news:5386060@discussion.autodesk.com...
Very close indeed, but if you do a Zebra analysis, you see that mine has
generally smoother transitions.
One question, do you see any difference between the sculpt part and just
stitching up the surfaces?
Of course the unanswered, real question is does this have any practical
application or just a fun study?

[Anonymous]

Forgive my buttonin if this has already been touched on. I ~believe~ you are
looking at eccentric cones (to give you the 'roller' element lines) with blended
intersections (any old way that doesn't impede function?).

http://www.woodlandsprings.com/portal/print.php?sid=253
http://www.patentstorm.us/patents/6322334.html

You inventin', Juergen? `;^)
Happy trails.

[pic and STEPs attached]

[Anonymous]

Juergen,

This is not exactly what you need but maybe you can use it to find a
solution. There is a lot of math but look at the illustrations. I did not
have time to try it so I cannot tell if it's going to work inside Inventor.

Based on this document oloid can be developed into a flat pattern. There is
a long way before Inventor can do it.

Good luck with your model,


grego

[Anonymous]

> Based on this document oloid can be developed into a flat pattern.
> There is a long way before Inventor can do it.

That's (oloid math.pdf) quite an in depth study. Thanks for posting it.

Attached might be of interest. Shows layout of element lines using construction
geometry (for the mathematically disinclined such as myself ). A
representative surface can be lofted thru element lines but that shape with it's
degenerate edges will present problems. Quad regions can be split into
triangles and a flat pattern developed from there if that's in the mix.

[Anonymous]

Finally I got it!
The trick is the sketch3 (see attached ipt) while lofting.
But one problem remains (maybe someone from Autodesk can have a look at this
problem): If the endpoints of the arcs are drawn exactly tangential to the
Quadrants of the other arcs (see the oloid_sketch.ipt, attached to my
posting from 11/06/06) the lofting fails. I have to move the ends of the
arcs a little to get it to work. Why?

Thanks to all who jumped onto this thread.

Juergen



"Jürgen Palme "
<=?UTF-8?Q?J=C3=BCrgen_Palme_?=>
schrieb im Newsbeitrag news:5385527@discussion.autodesk.com...
Did someone of you ever model an oloid? I spent a lot of time but can't find
a solution.

Juergen

[Anonymous]

> But one problem remains (maybe someone from Autodesk ...

They'll probably have to give the mathematician time to
become accustomed to the light (they keep him / her in
the dungeon, I think). ;^)

In the mean time you might want to track ...
http://news2.mcneel.com/scripts/dnewsweb.exe?utag=&group=rhino&xrelated=242959&cmd_related=View+thread
... and see what comes of it. Either condition is likely
to cause problems given the right (or wrong) input or
downstream needs. Degenerate edges will be the relevent
issue here (if you are going about it as I think you might
be, can't see the native IV, post a STEP?).

(The conditions cause varying problems in various systems
and present one of the great translation bugaboos, fwiw.
Caution is universally appropriate where either is involved.)

Google search for "degenerate edge" + NURBS turned up ...
http://www.ashlar.com/sections/support/articles/articles/acis-monster.html
... kinda cute and informative to boot.