duplicating and moving curve on surface

[2ms1]

I would like to take the curve that forms the bottom edge of the surface
shown below, copy it, and shift the copy up on the surface. I would
basically like to take the projection onto YZ of the curve, and slide that up
the surface a bit. I suppose this would be something like copying that
projection and then pasting in as a COS at location higher up in Y.
However, I'm not sure that'd be the way to do it, and I don't seem to be
able to use Edit>Copy for the curve anyway. I'm a beginner with Style but
don't know how I would do it outside of Style either.

Any suggestions?

 

[2ms1]

I have tried going into Style and making a projection of the curve on YZ
by just making YZ the active plane and making a spline curve that traces
the bottom edge just by me putting in a million splines that look like they
are on the original curve when viewed in active plane orientation. It
seems to basically give me what I want except for a couple things:

I can't seem to edit the curve after I have made it. I do not understand
why I am not able to select it with the edit curve tool. Along with being
able to fine-tune the spline-points/shape, I especially need to be able to
make the ends of the curve normal to the planes that are normal to each
of the two ends of the surface. Anyone have an suggestions for me?

Here's the curve I have. Notice the ends of the curve have the curvature
that the curve between splines likes to make automatically rather than
being tangent to the surface/normal to circle at the ends (which I would like to sweep along it but am not
able to, I think because the circle and trajectory are not normal
to one another).



Edited by: 2ms1

 

[sanjeevkar1]

hi


if i am getting it right. won't copy and then move work?


please post the file here. i (rather we) would love to see it.

 

[2ms1]

Unfortunately I'm using the Student Edition which is incompatible with
other Pro/E versions

I did finally figure out what I was doing wrong and got a copy of the
bottom curve to shift up along the surface.

However, I still have a big problem still though: The surface needs to be
able to change and have the curves created in style update in parallel. In
fact, in this case, all I need is for the Style curve to follow the position of
the bottom curve of the surface. Right now, if I change the bottom curve
on the surface, the style curves just stay the same.

Is there any way to tie curves created inside of Style to curves created
outside of Style so when you change things outside of Style the curves
inside adjust in parallel?

 

[CRang72]

If I'm understanding correctly, you should be able to use edit > offset. You can select the curve and offset it along a reference surface a certain distance. When the original curve and surface change, the curve created by offset changes as well.

 

[2ms1]

The curve offset is nice and I didn't really think of that. However, I need to also be able to adjust that curve like it's a spline. What I was doing in Style was tracing the original curve using the Style curve tool which creates a spline, then dragging it to new offset on surface, and then modifying the shape just a little bit (changing the curvature at one end).


The problem was that when the height or length of the surface changed, the traced and copied curves would stay the same. Now, I realize that an Offset curve would not have this problem. However, in order to create the small shape modification I want on the copied curve, I would still need to create a new spline that I do not know how to keep offset from the bottom of the surface by the same amount no matter how much the surface changes.


So, if I'm not mistaken,I'm still left with the question of how to link Style curves to other curves in model.

 

[jeff4136]

I don't have ISDX but have the impression (from somewhere) that you can't.


If you can describe the driver for trying to create this curve someone might be able to suggest an alternative approach (like projecting an offset curve to plane for reference to create a Sketcher entity to project back to the surface?).

 

[2ms1]

Ok, so to describe what I'm trying to get... I have a part that I am trying to create a tunnel through. The part is generally rectangular cross-sectioned, but it twists and turns a good bit. The surface you see above is the surface created by the centerline of the top surface of the part running to centerline of the bottom surface of the part. I created the surface because I am trying to create a tunnel through the part that runs through the "middle" of the part in the same sense that the two curves forming the top and bottom of the surface shown form the "middle" of the surfaces they are on. The tunnel is inside the part, so I created thatsurfacein order to represent the "middle" of the part across the range of y values.


You can actually see the circle that forms the tunnel when protruded and the y position of the tunnel path by looking at the curve I projected onto the surface in ISDX using the COS option for drawing a curve inthe last oneof the pictures above.


The two things about my goals with this partthat makethingstricky are that they include having the tunnel curve update at the same time as the top and bottom "centerlines"of the part when different versions of the part are made (different lengths, curvature, etc versions of the same part), and that I need the ends of the curve to actually exit the part at certain angles (not in 3D, but juston thesurface shown)rather than just being exact offsets of the bottom curve. I would like to be able to have the tunnel curve basically be a copy of the bottom centerline only modified a little at the ends and then slid up the "middle surface" a fixed amount that never changes even when the part changes.


phew I hope that was clear and actually useful
Edited by: 2ms1

 

[jeff4136]

Clear as mud. ;^)


Nah, think I got it and my original suggestion is where I'd probably
start. Project your offset curve to a Sketch (Edge -> Use) and trim both
ends back to allow 'spicing' in entry and exit curves. Then Project the
Sketch back to the surface.


An alternative would be to Sweep a 'ribbon' (line constrained mid pt to
trajectory) along most of the length of the on surface curve. Blend
extension ribbons to the ends to effect the entry and exit angles and
create new intersection curve(s) to Sweep the circle.


Or, you could forget all that and trim your on surface curve and create
Datum Curve thru Pnts extensions, then ...


There are probably a couple more options that might be worth trying. The
actual shape of the part might make one or another more 'attractive'. I
also expect some tweaking of trim points and process might be necessary
when part configuration changes so 'nice' might have to be weighed against
'robust'.


(I'm not sure there isn't a Style solution. That's just not within the
realm of posibilities I have.)

 

[2ms1]

Thanks for all the suggestions! Regarding the first of your three major
suggestions on approach, it sounds like great idea but I don't know how I
would project the curve back onto the surface. How would I do that?

I don't quite follow so well the 2nd and 3rd ideas though. I picture the basic
ribbon and understand how I would make, but I don't quite follow what you
mean by the extension ribbons and what the fundamental idea behind using
ribbons in the first place I guess. Regarding the 3rd suggestion, I'm not
quite sure how I would be able to consistently have the curve through points
to automatically adjust to produce the same "exit angle" whenever the curve
changes for different versions of the part.

 

[jeff4136]

Menu: Edit -> Project


The rest would be best demonstrated. Whip up and post an example; native and
neutral if no one with SE wants to try tackling the native.

 

[2ms1]

I am trying the first approach right now but I'm not quite sure what you
mean by "splicing" the curves. Could you please elaborate on that bit. I
know you can take two curve and then draw another curve between them so
the are visually connected, but I do not know how to match the curvatures at
endpoints and have the resultant combination appear as one curve in the
model tree as opposed to 3 separate curves.