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idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

(OP)
There are many situations in which one might wish to create a body by "shrinkwrapping" around a body or bodies.  Some examples include:

1. CAE preparation (wipe out tiny edges, defeature, etc)
2. Simplified representations of parts (for example, redacting for sharing of "dumb" models, modeling the real-world surface transitions in laminated composite parts; also, creating good-looking Wrapped parts)
etc etc

As far as I can tell, the main functionality in NX for something like this is the Wrap Geometry (and Wrap Assembly etc) commands.  But in practice, the resulting solids have very little detail.  In particular, if the geometry you're Wrapping has any "sticky-outy" things, you're going to end up with a "simplified part" that looks nothing like the real part.  In this sense, Wrap Geometry really is producing something like more of a "model envelope".  It's like the current Wrap Geometry is wrapping the model with very stiff paper.

What would be VERY useful is an enhanced "wrap model" feature which would have much more fidelity to the real model... Think along the lines of Wrap Geometry with cellophane, rather than the current "stiff paper"...

As a precedent, I think that some commercial CFD codes have good implementations of comparable idea.  Check out Star-CCM, for instance: http://www.cd-adapco.com/products/STAR-CCM_plus/common/surface-wrapper.html

Here's a quote from that page:

"The surface wrapper works by 'shrink-wrapping' a high quality triangulated surface mesh onto any geometrical model, closing holes in the geometry and joining disconnected and overlapping surfaces, providing a single manifold surface that can be used to automatically generate a computational mesh without user intervention."

I've seen this in action and it really does what it says.  If NX had such a functionality built-in, I think it would find a large number of uses.

What do you think?

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

I think it is very useful too. It has been around for at least a few years now.
I have used when I placed an engine in an assembly of a large riding lawn mower. Since I didn't really need all the detail of the components that were in the engine it gave me what I needed.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

have you tried linked exteriors?  Sounds like what you want

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

maybe "linked exteriors" is what we used for that (I am not at that company anymore)

What we did use "shrinkwrapping" for is when we placed the large lawnmowers in a simple model of a semi-truck trailer to see how many we could fit in there.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

(OP)
linked exteriors is nice, but it doesn't always output a watertight solid.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

To get a better linked exterior, set the resolution to Very Fine, and set the chordal tolerance to a very small number (a thousandth or less).  This will give you a watertight representation.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

(OP)
hmm, MCGNX, your suggestion helped but didn't produce a watertight model.  I kept looking around, and found a tool that looks very promising... "Simplify Assembly"

Assemblies > Advanced > Simplify Assembly

Walk thru the wizard and you end up with a nice single solid body... there are options to remove holes etc.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

ahh yes, I always forget about simplify assembly because I don't like the way it creates ENORMOUS files when you simplify an entire assembly.  I do however like that it completely solidifies your part into one solid...something linked exteriors does not do.

RE: idea for 'Shrinkwrap', enhanced "Wrap Geometry"...

There's an option which you can use with the Wrap Assembly function which will allow you to define so-called 'Splitting Planes', which you can use to help define a resulting body which more closely resembles the original assembly.  Look at the attached 3 images, the first shows the original assembly.  The second shows that assembly with just a simple Wrap feature created (note that I use the 'No Offset' option and I tightened the tolerance by a factor of 10 so as to get a better closer result).  The third image shows that same Wrap feature edited by adding a few carefully selected 'Splitting Planes' which helped to define or more usable shape.

Note that it's very easy to start with a basic Wrap feature and just edit it by double-clicking and defining a 'Splitting Plane'.  You can continue to repeat this process until you get a Wrap object with sufficient detail for your task.

John R. Baker, P.E.
Product 'Evangelist'
NX Design
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

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