Wrapping a sketch around a complex surface to extrude into a solid

[tallard]

Hello all.

I am currently running version 1915. I am working on a project for 3D printing and I need to break my balloon model into separate solids where each solid represents a piece of the balloon. In this example I have the logo for the US Marines. I have the artwork of this logo as a sketch but it wraps too far around the balloon to be extruded in one direction only. Wrap curve does not work on this type of surface (in the NX version I have). I have tried a number of things, like wrapping the sketch onto a cylinder and cone that is similar in shape but that doesn't really work. Below is an example of the "easy" part sketch so you can see what I am trying to do. The difficulty is with the extreme left and right side of the sketch I need to project. Thank you!!

 

[jerry1423]

Have you seen this previous post?

https://www.eng-tips.com/viewthread.cfm?qid=345896

Maybe something in there will help you

Jerry J.
UGV5-NX1899

 

[tallard]

Thanks Jerry, I did. The kicker here is the NX does not consider the surface I have to be "developable", therefore wrap curve is not an option for me.

 

[jerry1423]

For now, I have just a suggestion.
Save the balloon to a different file, because you are going to wreck it.
Do am OPTIMIZE FACE to all the faces only on the balloon, select all the faces with a rectangle. It will remove the parameters of it, but that's fine for now. You may need to use your command finder to locate the OPTIMIZE FACE command.
Now try to do a WRAP. I hope it works.

Jerry J.
UGV5-NX1899

 

[tallard]

Thanks Jerry, I tried it. NX still does not consider the face to be "developable" after optimize.

 

[3DDave]

This seems like a good use for Blender. I was in the middle of looking for a good video about it when the partial comment got posted.

One can take a vector file and convert to a mesh in Blender and there are tools for taking one mesh and bending it to match another. So far the best is a paid-for plug-in (it was $7.50 at discount; did not look for a current price.) That is less than I would expect 15 minutes of work, but needs some existing familiarity with Blender.

 

[tallard]

Thanks Dave, I have looked at Blender before and there seems to be some good tutorials on YouTube for it. Between NX, SW, F360, Hypermill, Esprit, I'm having a hard time getting motivated to learn another design package. I must be getting old.

 

[3DDave]

I previously used wireframe, surface, CSG, and parametric BREP modelers and then I see this and recall how difficult it would have been in any of them:

https://www.youtube.com/watch?v=1F2v5bqztwQe

Full price - $12. Dang.


Curious - what are the holes and inner part for?

 

[tallard]

Hi Dave,

The inner "cage" serves 2 purposes. 1), It keeps the lights from sitting directly on the outer shell because it looks weird if they do and 2), It adds material to the center at the top of the balloon to help it print, otherwise the printer can have trouble bridging that full gap. Thanks for the video link, I did watch a few blender tutorial videos on Saturday.

 

[SDETERS]

Would the Emboss command work here?

 

[jerry1423]

Please check what the sketch curves are.
Are they lines & arcs or splines ?

Jerry J.
UGV5-NX1899

 

[tallard]

Thanks you, No, Emboss doesn't seem to work because the emboss direction is fixed and the geometry really needs to wrap around the object unless there is another option within emboss that I am not familiar with.

 

[tallard]

Hi Jerry, they are generally splines as all the images I need to work with are converted from an image file to DXF then imported into NX.

 

[tallard]

Wrap attempt after Optimize Face

 

[cowski]

I'm not sure if this will work, but here's what I'd try:
Create a 1/2 revolve feature that approximates your balloon shape (imagine a lightbulb shape that is tangent to your outside surfaces, but without the bumps) and use "flattening and forming" to flatten the 1/2 revolve approximation. Use this to transfer your flat curves back to the approximated shape. Use the resulting curves/surface in a thicken operation and trim them to your actual balloon shape.

It might actually be better to use a shape slightly smaller than your balloon and thicken them outward...

If the thicken doesn't work, you could also try projecting the resulting curves onto your actual balloon shape. The approximate curves might work better than your flat sketch as a starting point.

www.nxjournaling.com

 

[tallard]

Thank you, sounds like a great option, unfortunately we seem to need an additional license for Studio Free Form. I would happily buy the additional license but we have not been able to get good support from the company where we bought our seat of NX.

https://www.indx.com/

 

[jerry1423]

Check this link out on converting splines.

https://community.sw.siemens.com/s/...831SAD/simplify-splines-to-get-lines-and-arcs

I hope it helps you.

Jerry J.
UGV5-NX1899

 

[tallard]

Jerry,

Interesting, are you thinking the problem is the sketch and not the solid model. Resulting in a failure to wrap.

 

[tallard]

I just created a new sketch with a few circles and lines and got the same message about a non-developable surface.

 

[cowski]

Wrap curve isn't going to work here directly as the balloon surfaces have curvature in 2 directions (the surfaces are not "developable").

Perhaps if you wrap the sketch curves onto a suitably sized* cylinder (or cone) then project those curves onto the balloon surfaces. The wrapped curves might give you a better starting point for the final curves.

*I'd suggest varying the cylinder diameter to see how it affects the final results and using the size that gives the best compromise.

www.nxjournaling.com