Loft Problem - Min. Rad. of curvature

[sirbartoo]

-Please see the attached file-

I have completed a feature using the Loft command. I lofted to a point, but I used guide curves to adjust the profile. It seems like I am getting a little point at the top of my feature that I can't see. I have detected it using the check entity tool. It tells me that I have a minimum redius of .005 e5. I have found a workaround using surfaces, but I would rather create the solid body with 1 loft feature. I have already contacted our local SW rep, but they were no help. Maybe somebody here can point out what I am doing wrong. Thanks guys.

 

[mjcole]

Give the Boundary Boss feature a try
Insert > Boss/Base > Boundary or you can find it on the solid protrusion flyout if you use that which has Extrude, Revolve, Sweep, Loft and Boundary.

This command is similar to the Boundary surface and has even more settings available. Typically you select your closed profile curves as direction 1 references and the guide curves as Dir 2 picks. You can define tangency conditions to ruled or other surfaces and define the interpolation method as
GL=Global,
NC=To Next Curve,
NS=To Next Sharp,
NE=To Next Edge or
LI=Linear.

I'm attaching a zip of the Boundary model I made from your submitted part file. I saved it with D1-Global D2-Global

The following D1,D2 settings caused Shell failures for min Rad.
GL-LI
GL-NC
GL-NS
LI-LI
LI-NC
LI-NE
NC-LI
NC-NC
NC-NE

I didn't get to check the other 10 combos yet NE-?? and NS-??

I think improving the input splines and curvature conditions can prevent a min radius problem by assigning Equal Curvature to a Construction Line in the Sketch. and then assign = curvature from the first spline to the second.

The boundary Solid feature has many useful curvature analysis tools and can allow you to see the quality of each of the 25 minimum ways of interpreting the input data.

http://files.engineering.com/getfil...d11935&file=min-rad_question_boundary-ntp.zip

http://files.engineering.com/getfil...edf-829e-95b6364b2a7a&file=bound_prop-mgr.PNG

Michael

 

[rstupplebeen]

Contrary to you request of a single solid feature I suggest creating this with a planar surface on the bottom and a boundary surface for the rest. Symmetry is also your friend. I hope this helps.


Rob Stupplebeen

 

[sirbartoo]

I've tried surface boundry, solid boundry, surface loft, and solid loft. I have also created just the top portion. I get a vareation of the same result with all of these features. Do all the curvature combs have to match up perfect? I don't think they do. There has to be something wrong with my sketch. All the splines have equal curvature and tangentcy. Am I over constraining the shape?
For a work around, I did a surface cut and surface fill. This gives me the geometry I want, but I have 2 surfaces. Is that acceptable practice?

 

[rstupplebeen]

Are you sure that the curvature tool is showing the correct information? In SW2009 on an ellipsoid it would show nasty curvature at the apex. I hope this helps.

Rob Stupplebeen