Star shape -- how to get a simple spine

[cgherghe-2]

Does anyone know how to construct that star shape with a simple white spine?
I cannot get rid of the central lines generated by the corners of the three spikes, tried blending to a point or to a smaller star point, to no avail.
And when trying to round those corners with an arc, I am having issues with connectivity between the arcs and the segments, and I am not able to get rid of those errors (no idea how to deal with them).

Any suggestion is welcome!!

[pausob]

What's your model's accuracy setting?

[cgherghe-2]

Thank you, I bumped it up to max, but nothing changed.

[KenFarley]

Saying the accuracy was set to "max" doesn't mean anything. For this type of touchy geometry it is always  advisable to have two things:

(1) Absolute accuracy. I believe this is the default for Creo in the latest versions, but still, if a start part from "the before times" is used, it might have the accuracy set to "relative', which is garbage.

(2) Set the absolute accuracy to a very SMALL value. What that is depends on your particular units of measure. For me, with inch based models, I use 1.0E-05. Often when models are doing weird things at tangencies, and the like, this will fix things. Then again, if you muck about with this setting on old models that were originally built with relative accuracy, this can cause troubles, particularly with complex surfaces.

Hopefully it's something like this that is causing your difficulties.

[cgherghe-2]

Absolute accuracy set to 1.0e^(-06) to no avail.

[pausob]

Can you share your model?

[Catalina]

Hi @cgherghe-2,

I wanted to see if you got the help you needed.

If so, please mark the appropriate reply as the Accepted Solution or please feel free to detail in a reply what has helped you and mark it as the Accepted Solution. It will help other members who may have the same question.
Please note that industry experts also review the replies and may eventually accept one of them as solution on your behalf.

Of course, if you have more to share on your issue, please pursue the conversation.

Thanks,

[tbraxton · Accepted solution]

Fully constrained sketch of the shape using your example pic as construction reference. This is not the only way to get this sketch done, it is based on the reference image you provided. I used the hexagons in 1 sketch as the reference to create the "star" shape.  As indicated by the shade region the sketch is closed. I did not have to use any trimming operations to get this result.

In Creo Parametric, one should in general keep sketches as simple as possible. This is why I used 2 sketches to make this.

This same sketch can be created in a single sketch using two concentric construction circles in rather than the hexagons.

[cgherghe-2]

The lines in the middle are still there, regardless of the closed sketch.
This was about obtaining a smooth surface inside the star when I perform the BLEND, I cannot get rid of the green lines that I drew in the attached picture.
 

[kdirth]

Are you trying to create a surface with a boundary blend from the sketch?  Boundary blend always creates lines between vertices on each side.

If you are creating a planer surface, use Fill.

[tbraxton]

You may find the videos provided by @DaveMartin on sketch functionality helpful. Check out the playlist for sketch mode constraints in particular but he has a series on sketch mode.

Creo Parametric - Sketch Mode Deep Dive 5 - Constraints

[tbraxton]

It is not clear what your objective is. If you are attempting to build some 3D geometry provide some pictures of what it needs to be. Here are two options of using that star to create solid geometry, are either of these representative of what you are attempting?