Hello out there,
is there anybody out there who knows how to create a rectangular helical sweep Feature, as in the shown black and white Picture?
I tried my best to get a solution, but it is not to be used. The gradient is somehow not constant in the red area to the blue area. The reason is the great difference between the inner radius and the outer radius. If the shape of the required rectangle increases, or edge lengths are the same length (quadrangle). Then the slope becomes more linear.
Is there any help out there?
Thanks Heiko
+Thank you for your also interesting solution (wrapped sketch) about my question.
Other views are always interesting.
- But what I miss however is the possibility to specify the slope.
- In addition, I find it not good that the Spin Center is no longer in the actual body center. This is beddened by the very long curve.
But again, thanks for your idea.
That's why I did a little Research to get a good solution. And here I need help again to have a solution ready for posterity.
Here I compiled a graph with an offset curve and a pattern. So far so good, .... it works mostly but not constant.
The curve in combination with the graph works very well. The Problem is the sweep Construction element.
Sometimes it works and sometimes not. If you change the profil in the sketcher or the pitch. Then the sweep fails
Could you have a look (or somebody else) on this, maybe you know why and what i did wrong about this Position??
Thanks in advance.
Unfortunately, I did a quick test and the wrap method will produce a consistent sweep.
Honestly, I'm not surprised that a sweep based on patterning copy-geometry type of features fails inconsistently. I attribute this to poor numerical-error handling deep in the software.
Your first concern about not being able to specify the pitch can be addressed with some relations. Note that the sketch to be wrapped is a simple line that starts at origin and ends at coordinates x,y.
So x = (number of wraps)*("perimeter" of the surface being wrapped)
and y = (number of wraps)*(pitch)
You get this perimeter by saving a length analysis.
But I completely see your concern about how the sketch that needs to be wrapped around the surface throws off the spin-center of the model.
It is a very frustrating aspect of modeling and drawing in Creo software, because blanking such "construction" entities has no effect.
thanks for your answer, it is also a nice version to get a helical sweep.
But does not solve my Problem, ..... unfortunately.
Your solution (YouTube Video) to get a helical sweep, is similar to the Feature "Helical sweep" under the Sweep Button.
There i get a very strange 3D curve, see in the first posting and with the YouTube solution:
The 3D curve isn't the Problem, this works with my "graph" solution very well. It is only the sweep who makes problems and isn't very stable.
sooooo it means, .... is there still any help out there?
Hello to all,
first of all thanks for all that help here!!!! Even there is still no perfect solution yet.
Antonius Dirriwachter thanks for your explanation about how is a evalgraph working.
I think I have understood the function with the evalgraph and the trajpar. As far as I can tell. "I'm still a rookie about this"
, I tried to understand the example what you have attached. So far so good. But your example has one serious error.
The slope consists of 2 Sweep's and not one. AND the blue Sweep is completely flat along the curve. Only the green sweep has the slope.
After this diagnosis I tried to use one curve (Skizze 1) where the profile is pulled along. But this only works when the start and end of the curve have a minimum distance.
However, this is technically wrong. It must be closed and only separated in one place.In order for the following curve (patterned) to be combined with the original curve. And no intermediate piece has to be patched.
>> However, if the curve is closed and only separated at one point, the sweep will fail. << I'm getting confused.
Still waiting for a good solution.
I used a normal sweep together with trajpar it should give the required geometry. to my suprrise the sweep feature in Creo 2 doesn't allow closed curves having a trajpar parameter
you are absolutely correct with your explanation about the angles definitions in the white picture from the first post.
Shame on me, about the white example picture. 
It was only a fast screenshot, what should show what I like to have.
And I didn't realize which section (area) has the slope. I thought it is linear or. constant. My mistake, sorry about that.
And yes you are right, the "blade" is constant.
And I want to have a linear or constant slope over the complete sweep Feature.
This is probably another way to model the geometry. It requires more steps but I hope it does give you what you wanted. I apologize if I have misunderstood the intent.
This would be my entry for this challenge.
It utilizes a wrap to manage the constant rise.
This is fairly simple to make parametric for a variety of shapes.
This method also does not require a "guide curve".
P.S. This is also Paul's solution above and with the clarification, I would suggest his answer is correct.
I like this solution a lot. It's very simple and robust. I could alter the shape of the extrusion section and the wrap works just fine.
However, there is one issue I found. It works fine on the straight extruded surface but not on the tapered surface, as shown below:
May be for tapered surface, we have to deal it differently. Thoughts ?
too true; the logic doesn't work for cones.
You should be able to develop the right shape, but it is not straight forward.
Are you remembering to use the coordinate axis in the sketch?
Important element in helping to place the wrap! 
Well, you can project that curve that was wrapped about the "cylinder", onto its conical version:
Pictured above is a sweep made using the "normal to projection" section plane control option.
The distortion is easy to observe:
If I reduce the size of the square wire, then you can get the "normal to trajectory" option to work for the sweep:
However - similar distortion exists, so I couldn't tell you which is a more realistic model.
