I have put this in the original thread but dont want others to missthis interesting tidbit

Curious..

Here, try this (it is not a solution to the problem but interesting none
the less.

Sample models of what I have discussed here are at
http://members.shaw.ca/b.eadie/Twist.zip

Make two parts part one will have a line sketch on the front plane, next
make a plane some arbitrary distance from the front plane and parallel.
sketch another line (both lines are mated at the midpoint to the origin)
the same length at 90 degrees and loft a sheet metal part on this and
flatten it. The resulting flat pattern has arcs at the ends.

Next make another part and draw a circle with a diameter to match the
length on the line in part one on the front plane and create a 90 degree
helix at the same distance the planes are separated in part one. do this
again and crate another helix but at 180 degrees out from the other at
the same rotation (counter clockwise if that is what you used). Next
create 2 3d sketches based on one of the helixs'. and another for the
other helix (sheet metal will not loft off of a helix) and then loft a
sheet metal part off the 2 3d sketches and look at the flat pattern. it
is perfectly square....

I wonder if on some of my lofted bends in the past could have been much
simpler if I had used a different modeling technique? This non
conformity for the flat pattern is most likely the reason we cant add
anything to a lofted sheet metal part as given it is the same part but
two possible flat patterns then there is some problems with the lofting
algorithm.

Ben

 

After making the first part, I flattened it, got a sketch profile from
the arc on the end and put that into a new part on two planes to do a
lofted bend. I mirrored the arc in each sketch thinking it might then
be straight after flattening.

I also put one sketch on the top plane and one on the right plane,
about ten inches apart for my ~5 inch long curve. After thinking about
the loft for 15 seconds, I got a "Error, Lofted Bends3, Loft operation
failed to complete." message.

I also tried two arcs, equal in size (and equal in length to the
original lofted bend straight line sketch) and rotated 90 degrees, on
the front plane and one 10" parallel to it. the flattened part had a
curved end roughly equivalent to the lofted bend part with the straight
line segments.

Interesting to play with, and would be helpful if lofted bend worked a
little better for flat patterns when making transitions and continually
varying radii parts, like hoppers and chutes.

Miles