Fit a sphere to a rather round surface in Pro/E

Hi everyone! I was wondering if there was a way in Pro/E to fit a
sphere to the contact area of two objects (as in a joint). Even
fitting a sphere to only one of the objects would be good.
Please let me know!
Thanks,
Roza

 

More information please. Is it a spherical part in an assembly? Or a
spherical surface or solid in a part? Does the sphere have to touch
the surfaces at the closest points to each other?

 

Thanks for replying. No it is not a spherical part. It is basically a
joint between two bones, which looks roughly like part of a sphere.
Now for some analysis I have to fit a sphere to this joint surface (I
basically need the center of that fitted sphere).The two bones
involved are two separate parts in one assembly, which were NOT
created in Pro/E. I imported them as STL files from another program.
I am not sure I understood what you meant by your last question, but
if I got it right, I would say it does not matter. I just needs to be
a good fit to the articulation surface.

 

Thanks for replying. No it is not a spherical part. It is basically a
joint between two bones, which looks roughly like part of a sphere.
Now for some analysis I have to fit a sphere to this joint surface (I
basically need the center of that fitted sphere).

Create a point on the csys which IS at the center of the sphere?

The two bones
involved are two separate parts in one assembly, which were NOT
created in Pro/E. I imported them as STL files from another program.

STL? BEGONE, begone. They're useless as imports. In fact, so useless they can not be assigned any mass properties. Do 'Analysis>Mass Properties>Calculate'. EVERYTHING is 0. No volume, no density, no mass, no nada! You must have had absolutely no choice and been bludgeoned into accepting this stupid export format (okay, the model slicers find them useful when it comes to creating layered RP models, but that's the absolute limit of their utility). But get something better for everyday use ~ STEP (STP), IGES (IGS) ACIS (SAT) or Parasolid (x_t, etc). Any of these will give you more modeling and feature creation options than the faceted solid of STL.

David Janes

 

You can get a volume for your stl file [once you have opened it as a part
file or assembled it], what you can't use is interference checking [asm >
model > global interferance] which is what you really need when you have the
two complex surfaces attached through some points.

Obvious answer is to use a stp then you can do interferance checking.

If you have to use the stl, do you have REX - the reverse engineering
extension? If so, use Restyle to create a surface over the joint area
facets and thicken it.

Its always going to be a bit of trial and error unless you can clearly
define your highpoints when choosing your asm points.


Sean

 

I don't know, Dave, at least he will have plenty of vertices from
which to create a curve through points between his two bones;-)

Seriously though, you could do this. A curve through points. Then put
a datum point at length ratio 0.5 on the curve. Use the curve to
create a sketching plane, sketch a center line aligned to the point
and normal to the curve. Sketch a semi circle one side of the center
line with the radius value set by end point of the curve. Use it to
make a revolved feature, revolved 360 degress.

 

Hi Sean,

I have some questions, and sorry if they're too trivial!! I am new to
Pro/E.

I created a stp file from my assembly, but I didn't see how I should
do interface checking. Can I create the sphere that I need?

I just read some about REX, and it sounds like if I could use this I
don't have to use GEOMAGIC anymore to create my STL files from the
point clouds that I have. It seems like I don't have this application
installed though. How do you know if it is installed with your Pro/E?

What do you mean by asm points?

 

Problem is that I do NOT have that sphere. That's what I'm trying to
figure out to do.
How would IGES be better in this case? I can also use that format.
Also, mass is not zero. It can do all the mass analysis with the STL
file.