square to round with free form swept 2

[Enduro99]

I've used many modelling programs over the years and have just begun to learn UG NX 2. I am having trouble creating a square to round using swept command with one guide string on center of two sketches. I've already tried the zero tolerance thingy, i'm beginning to lose my patience. This operation should not be this difficult to perform.

(Still Twisting)

Thanks in advance

Enduro99

 

[looslib]

The UG BBS CAD conference just this week had an example of a round to a hexagon with twist.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand

 

[abbasali]

Break your circle in to number of curves you have in the opposite side. Break it approximately at the same location of opposite side. It will not twist any more.

 

[Azrael]

Abbasalis suggestion is the easiest way to do it.

Just to explain the problem. If you rotate your square 45 deg. so you get a corner oriented at the starting point of the circle and then choose the arclength parameter you will get what you are looking for.

With the alignment method option set to parameter the software is trying to match the two profiles control points with each other and the square has more than the circle so get that option to work you need to break the circle down to four pieces.
But if you use the arclength option you are matching procentual lengths of the profiles with each other. Note that by rotating the square 45 deg. you align the start point.

Hmmm don´t know if my explaination made it easier or worse

 

[Enduro99]

According to "Practical Unigraphics Modeling For Engineers" I quote "Section strings are not required to have corresponding numbers of curve segments, but if they are the resultant surface shape will often be smoother". I already tried breaking the circle into four seperate arcs, still failed. This was an old trick I used in other CAD programs. The rotation of arcs or square sounds feasible but Abbasalis's solution sounds the most professional. Back to the drawing board.

Thanks to all for responding!

Enduro99

 

[cowski]

The pick order is also important. When you pick entities from the square, make sure you start at the corresponding position on the arcs (ie if you start picking objects in the upper left corner of the square, you must also start in the upper left 'corner' of the 4 arcs).

 

[cowski]

One other thing I forgot to mention, the direction vectors must point in the same direction on both sketches. After you pick the first object an arrow will appear, these MUST be the same for the square and circle, or twisting will result (where you pick the first object determines the arrow direction).

 

[Enduro99]

The pick order and direction, the four arc's rotated at 45^ off center and parameter setting for blend gave me a squrae to round. The problem i'm having now is to edge blend the four corners of the square leading toward the round. Only two of the edges are selectable in my case. I created the sketch for the square with chain option and wonder if this is the cause. Any ideas?

Thanks in advance!

Enduro99

 

[Enduro99]

I changed the tolerance value to 0 and it now allows me to select all corner sections.