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Variable section sweep with multiple sketches?

Amethyst

Variable section sweep with multiple sketches?

I'd like to build a locked sidewall that has varied draft.

I was under the assumption that the best way to build this feature would be a Variable Section Sweep as my sections would vary along the length of the side rails.

Can you have multiple sketches in a Variable Section Sweep?

If yes, could someone explain the method of picking up additional sketches along the length of the trajectory?

If not, what would the appropriate tool be for what I am wanting to accomplish?

28 REPLIES 28

Re: Variable section sweep with multiple sketches?

You might look at it as additional "guides". As long as you don't "lock" the swept section, the section will adjust to the trajectory and guide sketch. When you select an additional trajectory(hold CTRL), it will be the 1st "guide" and additional sketches will be the additional guide features.

swept_VSS.JPG

Re: Variable section sweep with multiple sketches?

Going further, what I'd like to see is the VSS command allow both multiple trajectories AND multiple sections. This way, you could get around a problem I have where you can't force an arc to be flat, or vice versa. also, you could do blend vertexes like in a blend/swept blend.

Of the 2, I like and use VSS's way more, for various reasons including using trajpar.

Re: Variable section sweep with multiple sketches?

Hi Antonius,

From what you show in this example there are 2 trajectories. What I was hoping is that Variable Section Sweep would allow for multiple sketches applied somewhat perpendicular to just 1 trajectory. From what Frank suggests you can not add multiple sections along the trajectory.

In another respect what you have shown could be quite helpful in respects to getting a tweakable side wall.

If I needed to modify a sidewall with lock variation and varied draft; would there be a good tool in Creo for placing multiple sections along the trajectory path?

Thank you for suggesting a different approach. I will try this and see how accurate I can match the customer's sidewall geometry.

Re: Variable section sweep with multiple sketches?

What you CAN do, is sketch a curve at the start, and at the end, then use those to drive the multiple trajectories. Note that you CANNOT tie any geometry used in the single sketch of the VSS to any static geometry (unless you set the option to "Constant Section", or it will either fail or give weird results. Now, you can if you're REALLY careful measure things and write relations, or make things egual, but it's VERY tricky to get it right. You can also lock some dimensions in the sketch, and drive others by the reference points of the trajectory, or drive ALL the vertexes by trajectories. It's very flexible that way.

Good luck.....

Re: Variable section sweep with multiple sketches?

In a sense, I am using your approach in a slightly different way. You can easily make multiple sections to manage your draft variation. Think of them as sections along the way to decide on where the guide curves, or trajectories, need to go. This works even better if you need to change elevations because the trajectories could be datum curves that are not planar if you need this.

Multiple sections sweeps are also very powerful and you really need to take a careful look at what you want to accomplish.

Also give careful thought on when to use Offset to keep these sweeps simple and adding details after the sweep.

Re: Variable section sweep with multiple sketches?

...And of course there is Swept-Blend which is "variable" by definition. It is not as rigid in following guide curves, though.

Re: Variable section sweep with multiple sketches?

The Variable Section Sweep "Almost" works well for me.

I am happy with how the surface rail matches up with the actual part. This looks like a tool that makes locks and varied draft easy.

Unfortunately I am finding that I can not get the start and end of the sweep surface to end up where the 2 guide rail sketches start and end. Since this segment is only a part of the side rails on the part profile I have to have the surface start and end exactly where my guide sketches end.

When I normal to trajectory or normal to projection I'm finding that there is a small gap to the end of the sketch.

If I choose a constant to normal projection the starting surface lines up perfect to the start of the guide rails, but the end of the surface falls way short on one of the ending guide rails.

I can't seem to find a way to build my own sketch that would lock to the exact end(s) of the guide rails.

Is there a way of ensuring the start and end of the surface lines up with the start and end of the 2 guide rails?

Re: Variable section sweep with multiple sketches?

I noticed that with my quick sketch too. Obviously, you could simply go further than you need with both guides. The problem is that the sketch is normal to the trajectory although you can select another normal for the sketch.

Often, complex shapes are created from many surface operations where in the end, it becomes a closed volume or a thickness can make these solids. That remaining gap, for instance, could be filled in with a Fill feature.

Can you share a image of your challenge or even a part of the file you are trying to affect?

Re: Variable section sweep with multiple sketches?

RailsWithPart.jpg

This shows a couple sweeps that I applied on opposing sides of the parting line. I might have to overbuild the sketch extents as you suggest. I just wish this would stick to the start and end of the sketches.