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STL Surface to sheet surface

Creator
Creator

Folks,

I have an analytical process that generates points which describe a surface.

This data is well ordered, ijk, xyz

Simplest format for me was STL.

All analylitical point data explicitly preserved.

 

I have now tried two ways to process this in NX so that I can get a set of sheets that can be integrated in to downstream design process.

 

Method 1, use the rapid surfacing tool.

When this works, it works great, but in cases where the STL data encompasses higher curvature, it becomes impossible to keep the edge reasonably congruent with the initial STL points, and as adjacent STL zones are no longer sewable.

 

Method 2.

Modified my analytcal tool to also outpout the edge points used for each STL file.

Read these in as seperate groups of points

Made each a fit curve.

Now the four fit curves can be used with fill surface to create a sheet.

But... the "Fit to Facet Body" does not let me pick a my original STL convergent body.

Does that STL data need to be converted to some other facet format?

 

Any help is appreciated

Thanks

ANdy

 

11 REPLIES 11

Re: STL Surface to sheet surface

Creator
Creator

So I answered my own question regarding the fill surface, fit to facet.

I changed the convergent  facet surface to an NX facet surface and the tool works

Poorly, but it works.

So far my sheet surface is as far away as .4 inches from my initial STL points.

This is not very good.

I will play with this method a bit and see if I can get it closer.

I think it needs a patch count control on the filled surface.

 

Any thoughts on how to turn an STL into a sheet?

Thanks

ANdy

Re: STL Surface to sheet surface

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

If your process generates well ordered points, you might consider using the "through points" surfacing tool; it can take point data from a text file and generate a B-surface.

Re: STL Surface to sheet surface

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

The rough offset command will take a facet body as input; you can specify an offset of zero to create a B-surface. If the facet body isn't good quality, the output surface won't be much better...

Re: STL Surface to sheet surface

Creator
Creator

Think of this as a wing, I have say 250 points around the wing at 75 slices.

I need the large number of slices to capture change along the wing, and the large number of points to capture some changes in local curvature (its not realy a wing)

The through pts tool only allows a 24 by 24 matrix of points.

Not big enough.

 

I could read in 250 sets of points 75 times and make splines.

And then re-read in the sets of points in the cross direction as 75 points 250 times

And then use those to create a surface.

But thats a lot of work, and the scripting process seems like a lot of work.

Re: STL Surface to sheet surface

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

I've only used the through points command a few times (on small numbers of points), so I don't know all the limitations. The help file makes it sound like 25 is the maximum, even for a multiple patch surface; however, I don't see why this would be a limitation. If you create a degree 3 spline through points, you can specify as many points as you like. The resulting spline may have many knot points (or patches if we extend this to a B-surface), but there is no inherent limitation to the number of points you can specify. I'm curious if this is an actual limitation of the command or just poor wording in the help files.

Re: STL Surface to sheet surface

Creator
Creator
No it is a real limitation.
Tried to give it more points
Failed miserably
Andy





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Re: STL Surface to sheet surface

Siemens Esteemed Contributor Siemens Esteemed Contributor
Siemens Esteemed Contributor

@AHRobertson 

 

Have you tried Fit Surface as an alternative to Rapid Surface?

Ben Broad | PLM Enthusiast | Siemens GCSS

NX (v17 - 1876) | Teamcenter (9 - 12)
Value Based Licensing | Adaptive UI | BETA Registration

Re: STL Surface to sheet surface

Creator
Creator

Fit surface has no ablility to hold the edges that I could find

I will look at it again

Thanks

ANdy

Re: STL Surface to sheet surface

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

I tried the "through points" surface tool on a file that contains 105 rows of data with 40+ points per row, set to create a degree 3 surface. It worked; the input dat file can be found here if you want to try it yourself. The thread that the link leads to also contains a journal file to help automate the creation of the surface. In my test, I didn't use the journal; I just started the through points command and gave it the .dat file.