Sweep along 3D curve in 5.0 Notes

[Chris Lohman]

I've been playing around with the new sweep along 3d curve in 5.0 and after talking with our developers I have learned on tid-bit to pass on to you. If you intend to sweep along 3d curves, don't use the Parasolid kernel. Change your part to the ACIS kernel before attaching a sweep online 3d curve to it. Parasolid is just too weak to handle the resulting geometry.

 

 

[cborer]

I tried it in Acis. It works perfect. My compliments.

5.0 looks very good!

[Guest Scott Wallis]

If you do it in ACIS can the resulting shape be converted to Parasolid, or does it depend on the complexity? I use Parasolid as my default kernal because I pass the files to my parasolid based CAM package. I have not downloaded 5.0 yet.

 

 

[Chris Lohman]

I played around with this. Using ctrl+k to toggle back and forth, once I had a sweep along the 3d curve, I would toggle to parasolid and see it fail, go back to acis see it restored to a valid part, fail, ok, fail, ok. It is the complexity. Parasolid just can not handle the complexity of 3d shape swept along a curve the way IRONCAD does it (wierd huh, it's usually the other way around).

 

 

[Bill Thompson]

If you must supply .x_t (Parasolid) files to a vendor, you could model the part with complex 3D sweeps in ACIS, and when the part is finished, make a copy of the file, combine the shapes (lose history), and switch kernels. I bet that would work. It's probably not that Parasolid cannot handle the resulting geometry, just the 3D sweeping process to get to that end result.

 

John Ohanian

IronCAD Development

[Chris Lohman]

Here's another sweep along 3d curve tip.

A sweep along a curve is essentially for fluid geometry. So when you are creating that 3d curve, that curve needs to be at least filleted by a small amount @ it's vertices. If in your 3d curve you have hard right angles, then when a profile is swept along it, it will hit this hard angle and fail. You need to fillet all of your hard turns on the curve so that a sweep can follow the fluid shape instead of hitting a brick wall. How large the radius depends on the size of your profile. The sweep needs to be able to follow that curve without intersecting itself so if the radius that it sweeps along is too tight, it would essentially have to "crimp" into that radious to make the geometry work and you'd end up with unpredictable results so we just don't let it do that. One thing that helps me is to think of bending the shape with a wire. Could I really bend a thick wire with the same thickness as my profile into that shape without it pinching? That's the thinking behind the sweep along 3d guide curve/

 

 

[Cary OConnor]

One more note: This information about the acis vs parasolid was in the beta. We have implemented kernel collaboration for the 3D Sweep for the final release. This means that it doesn't matter what kernel you are in when performing the sweep. We will complete the sweep command in whichever kernel handles the requested operation better without the user having to worry about it. The benefit of Dual Kernels.