Hi I have a small problem using a sweep feature in Creo 3.0.
Using this sweep feature i can create sketch on a normal plane to trajectory line.
for example i am sending some screens what i want to do (this example i have made in solidworks)
p.s. sorry for bad englisch:p
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I think SW is doing something that Creo cannot, at least directly. It's taking an existing sketch (the blue triangle in the image below that Antonious posted) and creating a cut by essentially "dragging" it along the pink trajectory. What's novel, compared to Creo, is that the sketch is not normal to the trajectory nor does it stay parallel, it rotates with the trajectory. It's a bit like dragging a metal edge over a clay model. Nothing in Creo that I'm aware of can do that.
Now, because the pink trajectory is an arc, you can create the same geometry be flipping the roles, which is what I did above and I think is slightly different from Rohit's VSS. Make the arc the sketch in your VSS and use two trajectories. The origin and the normal trajectory is a line through the center of the fillet, the other is the hypotenuse of the triangle. By aligning the center of the arc with the origin and tying the arc to the hypotenuse, you end up with the same trumpet's bell shape:
When made as a cut, it creates the same shape and creates a tangency to the fillet and not to the sides. This is using the same geometric principles in different ways, which should create identical geometry. That it's not identical puzzles me some, I assume that it's a SW to Creo translation error or perhaps an accuracy setting in Creo or SW. It's very, very close, however.
Hi Doug...
I haven't looked carefully at the various VSS solutions (Rohit's, etc). However, with two trajectories (RED and PURPLE below), you should be able to create a multi-trajectory sweep to create the same cut. But whether or not this is accurate, I keep coming back to the same thing (and I mean this with no offense and all due respect). Why in the heck would we make such a thing? It seems to me that SW is creating geometry almost no one would actually expect or want.
Unless the original poster is an expert SW designer trying to create some exceptionally intricate and crucial piece of geometry which Creo is struggling with, I have to believe he just wanted a round tapering to a point at a discrete location along an edge. If that's all he wanted to do, Creo can do this in one feature. The SW geometry is not what I would expect to see and it's not what I would want my machinist to create for me. Therefore, I think it's poor. If SW provided several solutions to the same portion of geometry allowing you to alter the tangencies and other details, that might be more impressive. Maybe they do?
By the way... the "3D sweep of solid geometry" to create cuts is on the way in Creo 5.0. This finally allows us to simulate a tool being dragged through 3D space removing material as is goes. It seems like maybe this capability would allow you to model the geometry in question.
Hmm... an interesting piece of geometry at minimum.
Thanks,
-Brian
Having access to SW and seeing how this is built, I don't thing the two highlighted curves will get the same results. Perhaps a screenshot out of SW without the zebra stripes would help (they threw me off initially):
He's created a sweep around that arc that creates a straight line when intersected with the side wall of the rectangle. SW lets him start with that straight line and just sweep it around the arc. One sketch, one trajectory. The profile sketch is actually tangent to the trajectory and remains so throughout the sweep.
I don't know why he would want this, but it doesn't really matter (though I will agree, that understanding what you are really after is more important in order to use the right tools to get you the right results). The question here is how would you create that in Creo? You can't do the same thing, Creo doesn't offer the functionality. But you can get there..
Interestingly, this illustrates SW's ability to take whatever inputs you give it and just make something. I've noticed that SW users tend to exploit that, resulting in geometry that works but they got there by means that aren't necessarily obvious. And later, when it needs to change, that can make it difficult. Here, for example, I've seen users (not necessarily this user) thinking go something like "this will result in an angled transition so I'll sketch one and then sweep it around the fillet." The triangle doesn't really matter, the angled line doesn't matter, only the smooth transition. But this is how they thought of it and SW built it, so there you go.
Creo doesn't really tolerate this kinds of free thinking well. It rewards careful planning, thinking through your intent and building to what you want. Expert SW users who have learned to work well within its more forgiving framework struggle with Creo. The reverse is true as well, after close to 2 decades of using Creo, SW drives me mad. It seems that it's always trying to guess what I'm after and make something from what I've given it, and it gets in the way of what I really want in the process.
Is your second image not it?
The trajectory of any point along the line must be an arc (so the arcs increase in radius along the line) and therefore it's just a matter of 'projecting' (wrapping? unwrapping?) the line back around the cylinder it sweeps, to a common plane passing through the axis. Since your 'trumpet bell' appears to cleanly intersect the line in your image above, it would seem to satisfy the definition.
It seems like in Solidworks the triangular profile is dragged along the trajectory as mentioned by you and then as it reaches the end of the trajectory it gets tired and goes of to sleep.
