Reverse Engineering Solid Body from Facet Body (STL)?

[Buckshott00]

Hello,

Running NX7.5.4.4 Win7 64bit

I was wondering if there is anyway of reverse engineering a Solidbody from a facet body? I have the NX freeform (basic I think) but not Shape Studio.

I have tried Rapid Surfacing, but it looks like it was meant for surface or sheet bodies and not for solids.

Any suggestions?

 

[jerry1423]

These threads may help you out:

http://www.eng-tips.com/viewthread.cfm?qid=238143

http://www.eng-tips.com/viewthread.cfm?qid=214186

 

[Tingsryd]

There are some basic tools in NX but they don't seem suited for a converting large models. There is software that does this nicely and typically have hefty price tags as well. Some that come to mind are Imageware, Geomagic and Transmagic. Although I use stl bodies for manufacturing once in a while, luckily I have not had to deal with file conversions of large stl bodies. I don't know what is current for converting products but hopefully this might point you in the right direction.

Also, if you don't need to convert bodies that often, you might want to consider a conversion service for occasional use.

NX 7.5

 

[Toost]

When and if you reverse engineer something in NX , you will ( at least in the current versions) create a number of sheet bodies that later can be sewn/ converted into a solid. Note that the "only" difference between a sheet body and a solid body is that the solid encloses a volume. The rest of the math is the same.

 

[Buckshott00]

Toost,

I have read that on here several times but so far no one has demonstrated it, and when I try it, it doesn't work well. I am going to attach a facet body (STL) of a fairly simple body.

I invite anyone to demonstrate with screen capture making a sheet body from a facet body that is accurate to the original STL file

 

[wackolacko]

For this simple part, you can just use view section tool to create profile then extrude.

John Lackowski
NX Support
Win 7 64bit NX 7.5.4.4 TC 8.3.1.1

 

[Buckshott00]

I only listed that part to show the surfacing tools. The idea being that if it is that simple to make a sheet body from a facet body then doing one like the one above should be no problem

 

[Xwheelguy]

Would a solid suffice? (see below my signature - feel free to let me know if that's accurate enough).

I believe the trick is understanding how to use the command...plus, your example was planar, so that removed much of the guesswork - no segmentation to the splines & degree of 3 maximum.

Now, once you get the dialog up, expand all the choices. You'll see the degree & segment options. I immediately change those to degree 3 & segment of 1. Turn on Preview & leave the rest as-is.

Now we're going to try & pick the extreme corners of each FACE we're trying to create using the corners of the faceted model for reference. Start picking at the corners and after you see a line (should be after 2 corner picks), click Accept Points. Start at the corner you last picked (or the end point of the line created) and create your second line. Rinse and repeat until you see 4 lines - accepting each line as it is created. You WILL get an error that it cannot create a surface. Ignore this until you have a closed bondary for a surface. Once you do, you may have ot rotate the model to see it. Create 1 face (surface) at a time, possibly having to use Trim here & there as in my attached example.

I figured this out by reading the documentation and trial & error. Surfaces with more curvature will be tougher to do. You're not going to get an EXACT match using this command, but if you're patient, you should be able to get it pretty darned close.

Hope this helps.



Tim Flater
NX Designer
NX 7.5.4.4 MP2
WinXP Pro x64 SP2
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[Buckshott00]

Tim,

That's exactly what I was trying to do. I figured if I could do it with the simple parts I would have better luck with the more difficult ones.

 

[Xwheelguy]

Buckshott,

Not sure what quality you're going to need - that might be another story. You may have to sacrifice some precision for higher quality surfaces. At first glance the surfaces in the solid looked good but when I looked at reflections at a very sharp angle, they left a little bit to be desired, IMO.

You will more than likely have to refine your surfaces a few times with your actual models - this was just something quick.

It's all going to depend upon what your end product needs to be and the process the part is going to require/pass through.

Tim Flater
NX Designer
NX 7.5.4.4 MP2
WinXP Pro x64 SP2
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB