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RobJV
Posts: 534
Registered: ‎07-14-2004
Message 1 of 11 (537 Views)
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Sweep without twist

537 Views, 10 Replies
09-30-2013 04:24 PM

I have a sweep using a 3D sketch.  The sweep will form "rails" for a ball run.  I have attached my part and picture.  I assume I have to use a guide surface to prevent the rails from twisting as shown.  Ideally I would like them to end as shown in the sketch in the lower right corner.  Any help in accomplishing this would be great.

 

If somebody has a better method that would be great too.

 

(The run is not exact nor finished and the there are extra unconstrained sketches in the part file.)

 

Thanks,

 

Rob

Inv 2013 Pro

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Mark.Downes
Posts: 109
Registered: ‎11-18-2010
Message 2 of 11 (476 Views)

Re: Sweep without twist

10-01-2013 01:39 AM in reply to: RobJV

Hi RobJV

 

I had a quick go at this (made up part), I used a 2D sweeped profile as a guide surface for the

main sweep.

 

Hope this helps

Cheers

Mark

Inventor 2013

 

Capture01.JPG

Valued Mentor
mpatchus
Posts: 451
Registered: ‎10-22-2008
Message 3 of 11 (458 Views)

Re: Sweep without twist

10-01-2013 03:56 AM in reply to: RobJV

I personally would make each rail its own part, and make this whole thing an assembly.

In the real world, this would not be a single part.

I've always told my students that they can never go wrong by mimicing the real world.

Mike Patchus

Inventor 2012 SP3 ~ Vault Pro 2013
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Mentor
RobJV
Posts: 534
Registered: ‎07-14-2004
Message 4 of 11 (425 Views)

Re: Sweep without twist

10-01-2013 09:48 AM in reply to: Mark.Downes

Thanks for providing the sample.  I will look over and post if I have any questions.

 

Rob

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RobJV
Posts: 534
Registered: ‎07-14-2004
Message 5 of 11 (422 Views)

Re: Sweep without twist

10-01-2013 09:51 AM in reply to: mpatchus

Yes, of course I will be making these as separate parts.  (This can still be done as a single part and broken up.) 

Mentor
RobJV
Posts: 534
Registered: ‎07-14-2004
Message 6 of 11 (414 Views)

Re: Sweep without twist

10-01-2013 10:29 AM in reply to: Mark.Downes

Thanks - your sample helped a lot!

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RobJV
Posts: 534
Registered: ‎07-14-2004
Message 7 of 11 (376 Views)

Re: Sweep without twist

10-01-2013 05:06 PM in reply to: Mark.Downes

I went through and created my own set of ball rails.  I only noticed one mistake in your sample that may help others.  Work Plane 2 should be built off of the top line of sketch 2 and not the angled line.  This will ensure that the track cannot intersect itself.  Thanks again for leading me down the right path!

Distinguished Contributor
Mark.Downes
Posts: 109
Registered: ‎11-18-2010
Message 8 of 11 (358 Views)

Re: Sweep without twist

10-02-2013 12:40 AM in reply to: RobJV

Morning Rob,

 

My Bad that one (well spotted), here is an updated model. Glad it helped.

 

Cheers

Mark

Inventor 2013

 

Capture02.JPG

Employee
GlennChun
Posts: 115
Registered: ‎06-10-2004
Message 9 of 11 (318 Views)

Re: Sweep without twist

10-02-2013 03:16 PM in reply to: Mark.Downes

Hi Mark, Rob,

 

The sweep body in rail-02.ipt does not correctly pass the required cross-sectional profiles.  See rail-02-check-cross-sections.ipt.

 

surface_normal_sweep.png

 

I recommend to use the pull-direction sweep (aka plane normal sweep) in this case.   Here's how I created the attached rail-03.ipt:  Open rail-02.ipt. Make the XY Plane visible. Edit the Sweep1. Press the Guide Surface button. While pressing the Ctrl key, select the existing selection of the guide surface.  Now the arrow button should turn red because the guide surface selection has been deleted.  Click the XY Plane.  Hit OK.  This will create a sweep body whose cross-sectional profile orientations are controlled by the Z-Axis direction.

 

In rail-03-check-cross-sections.ipt, you can see the sweep body correctly pass the required cross-sectional profiles.

 

pull_direction_sweep.png

 

For the pull-direction sweep, the path doesn't have to lie on the plane or planar face used as a guide surface.  Inventor passes the normal vector of the plane to ASM, not the plane or planar face.  Only the vector information is important for the pull-direction sweep.  When the guide surface is curved, the path should lie on the surface which is passed to ASM.

 

Hope this helps,

 

Glenn

ASM Development

Autodesk T-Splines Component Development
Distinguished Contributor
Mark.Downes
Posts: 109
Registered: ‎11-18-2010
Message 10 of 11 (304 Views)

Re: Sweep without twist

10-03-2013 12:54 AM in reply to: GlennChun

Morning Glenn,

 

I followed your example using the XY plane, I also deleted the un-used guide surface. That’s a great example, I will be printing this to file away in my book of “did you knows Tip-bit’s”

 

Cheers

Mark

 

Capture03.JPG

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