references in sketcher

[2ms1]

I am trying to cut the end of an ellipsoid offand replaceit witha piece of sphere. To achieve this, I was hoping touse two identical but orthogonal curves like the one shown in Figure A belowcombined withthe circle formed by the top edge of thechopped off ellipsoid to form the spherical bit using Boundary blend.


The problem is that I am only able to get one of the curves (Figure A). I was able to draw the one curvebecause I was able touse the edges of the ellipsoid as references. However, when I try to draw the orthogonal curve, for some reason sketcher will not let me set any of the ellipsoid as a reference. Anyone know what my problem is?


The ellipsoid is a surfacecreatedwith the same method way I am trying touse to makethe spherical bit -- boundary blend of a circle and two curves in the other direction.


Figure A:








Figure B (not able to select the necessary references):



Edited by: 2ms1

 

[design-engine]

the robot finger again?

 

[jeff4136]

If I understand the problem correctly; silhouettes of analytics (?
not sure that accurately describes the limitation) only may be
projected for sketcher references. You can create a plane / elliptic
surface intersection curve and project that -or- you should be able to
use the X-Sec reference option.

 

[2ms1]

the robot finger again?

\


Ha, no this one is not the inifamous robot finger

 

[2ms1]

Using X-Sec selection got it. What is X-sec anyway? I've never known and just kind of forgot about it/never paid attention to when I've seen it places. I notice one of the three curve creation options is "Use X-Sec", but I've never known what that meant.

 

[design-engine]

well I think PTC got that tool mixed up when they developed the interface. Variable section sweep is a multiple trajectory sweep. Its multiple trajectories not sections. The other tool thats hiding in WF 3.0 is the multiple section tool with one trajectory X-section refers to the spine of the sweep.

Edited by: design-engine

 

[dr_gallup]

If you are making a true spherical end then you only need an arc segment in one plane and revolve it.

 

[jeff4136]

> What is X-sec anyway?


The X-sec sketcher reference is a sketch plane / selected entity
intersection curve. Has nothing to do with Variable (variable,
not multiple, as a fuction of multiple trajectories or as a
function of t, or both) Section Sweep sections. X-trajectory
maybe?

 

[shankar_me]

Hi 2ms1,

If you are making a true spherical end then you only need an arc segment in one plane and revolve it.

dr_gallup is right. I am posting figures of the model I did based on your description.








When sketching, I set the tangent edges display as solid. Then Iselected them as references and did the sketching.


Regards,
Shankar

 

[2ms1]

Yeah, I guess I should have posted, I did go back and do it with revolve -- the more elegant and fundamentally sound way of doing it. It did bother me, however, the not being able to get the references in the sketcher so I'm glad I tried the boundary blend way and, as a result, learned what I have in this thread. It still seems weird to me that you would have to use a different selection method to get the references I was looking for, but at least now I know about it. Thanks for the detailed directions on how to do the revolve method though.