I want to design a channel that have a rectangular shape in the start and circular section at the end with a complex trajectory and some geometrical constraint (e.g. bolt boss). I used swept blend command with 6 sections and a trajectory. Then I used round command to remove sharp edges .The problem is that the channel is not smooth and the round command created extra sections which is not suitable for flow analysis software.
How I can have a better geometry without extra edges and also smooth shape?
The boundary blend was pretty messy so I opted for two sweep/blends. The 1st is the round section, the second is the tube. I used the external copy geometry to make sections with the radius already included. The final blend you can see is a copy of the circle using 8 segments instead of 4. Blending worked best to enlarge the radius rather than pinch it. This is a matter or preference, of course. I did choose to join one end to the previous blend.
Some observations on the sweep/blend; note that there are definite transitions where the sweep origin has endpoints. Making this a continuous spline may smooth a feature such as this tube. Otherwise, a blend section should be included at those vertices along the origin to better manage transitions.
Anyway, this is what I ended up with using the external copy feature:
Rounds have a tendency to do that because they need to make true rounds and match tangency. 1st suggestion would be to create the rounds in the blended sweep sections. The section where the rounds quit can be done with a boundary blends between two segments.
These are always a challenge. Rounds in particular prefer to be curvature continuous for most ID people, but that can cause other issues in the software. It all comes down to a gentle art of persuasion in the software.
You're on the right track. And in general, those mismatches on the radii are not an issue in manufacturing. If this causes a problem in your analysis software, you might forward your model to their customer service group to see what they cannot handle what is quite basic geometry.