Creating surface from topographic data

[ereisch]

I'm trying to design a structure around a certain terrain feature, so I have a need to have an accurate depiction of the surrounding area into NX (preferably as a surface). However, I'm having difficulty trying to get the data I have into NX in the proper scaling format. I have a PDF (though I converted it into a TIFF image) of topographic data for the region in question. I was trying to insert it into a part as a raster image, and then trace the contour lines using studio splines on planes at the heights specified in the topographic file, so I could then create a studio surface using the splines as intersection curves. The problem seems to be I cannot modify the size of the imported raster image; no matter what I specify in the dialog, it always seems to want to create it with a size inherited from the file resolution, which ends up making the image something like 8"x7" on the screen, when I really want it to be something like 400'x300'.

I also tried tracing the image as-is with the intention of scaling up the resulting splines, but alas, it appears as though NX doesn't have an option to "scale enlarge" a particular sketch or object.

Anyone have any alternate suggestions / things I'm doing wrong? Using NX 7.5.5.4 mp10.

Thanks in advance.

 

[cowski]

...it always seems to want to create it with a size inherited from the file resolution, which ends up making the image something like 8"x7" on the screen, when I really want it to be something like 400'x300'.

If it did allow you to scale it up that much, the result wouldn't be usable.

You were on the right track to create your spline over the existing image then scale up the spline. You can use Edit -> Transform -> Scale -> Move (or copy) to scale studio splines.

www.nxjournaling.com

 

[JohnRBaker]

I assume that you're using the...

View -> Visualization -> Raster Image...

...function, correct?

If so, after adding the albeit 'small' TIFF image to your NX file, simply double-click the sheet body feature and drag any one of the corner handles until you get to the size that you'd like to work with. If you watch you will see that the size of the dragged image will be shown in the 'Height' and 'Length' widgets in the dialog, and while it looks like you can edit these value directly, as you've already discovered, that doesn't work, it's just a sort of 'read-out'.

That being said, for NX 9.0 we've completely reimplemented the 'Raster Image' function. To start with, you're no longer limited to only TIFF images. In addition to TIFF, you will also be able to create a 'Raster Image' object using either JPEG or PNG formatted image files. Also, you will have direct control over the size of the image relative to the model space. In addition the default 'Image Size', you can also enter any 'User Defined' size that you wish.

And one of the biggest changes is that you will NO longer need a 'studio_visualize' license to gain access to this function. All you will need is a normal Modeling license.

John R. Baker, P.E.
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Product Engineering Software
Siemens PLM Software Inc.
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[ereisch]

Ok, I believe I got the scale to work, but now it's refusing to mesh the curve. Perhaps this is ignorance on how to use the studio surface or "Through Curve Mesh" features, but I have a series of contour lines, each in their own plane (of elevation). However, NX is not letting me mesh a solid surface using the contour lines as guides. youtube videos on how to do something like this are less than helpful. Any tips?

 

[JohnRBaker]

Can you provide the file of the 'contours'?

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
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[cowski]

Does it give you any specific error message?

www.nxjournaling.com

 

[Toost]

Hm, Does your curves connect side to side or are they "islands" inside the outer boundary ? ( I would imagine that they are islands.)
If so you need to instead wrap a surface to those curves. The curve mesh cannot be used.
Create a surface, as large as the outer boundary.( You can probably use the one that the raster image feature created.)
Then wrap, ( Edit Surface - Refit face - Fit to target) Select the face, select the curves to fit to, Then trial and error the degree and patches until you get something like what you desire. ( Start with degree 3x3 and patches say 10x10, maybe also set the fitting direction normal to the sheet.)


Regards,
Tomas

 

[Xwheelguy]

If the innermost contour is the end, and you don't require a "cap" to your "hill", just use Through Curves and play around with the alignment until you get something close to what you want. Make sure all the arrows are pointing the same direction for each section (contour).

Tim Flater
NX Designer
NX 8.0.3.4
Win7 Pro x64 SP1
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[JohnRBaker]

Or you could extract a series of points from the curves-of-constant-elevation (AKA 'contour lines') to form a 'cloud of points' and then using...

Insert -> Surface -> From Point Cloud...

...create a B-surface through those points.

Note that starting with NX 8.5 the 'From Point Cloud' function has been replaced with a more modern, in terms of both the UI and the various options for the type of final shape that is created as well as it being an actual feature associated to the reference points, called 'Fit Surface'.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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

 

[ereisch]

Here is some of the file (the finished product will have about twice as many contour lines). It is not a contour of a fully-closed hill; the contour lines terminate at the end of the area of interest. I want to create a surface that interpolates (evenly or preferably via a spline algorithm) between the contour lines, and simply stops at the end of the lines (if I need to draw lines to connect the endpoints of each line together, I will). I think I will then scale up the resulting surface to meet the overall dimensions of the original source data. I tried doing the scale function on the individual splines, however their vertical displacements placed them off the Z-field drawing area in NX, so I could only get in 2 or 3 contour lines, beyond which it wouldn't show me any others.

Thanks

 

[JohnRBaker]

OK, I just used a simple 'Surface Through Curves' and got the results seen in the attached part file.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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

 

[Toost]

And here's one using the Refit face method. I created a 4-point surface as the base then used the refit face.
3x3 degree and 15x15 patches - I don't know how tight the tolerance surface to the individual curve must/should be. The supplied example is ~0.01 inches off at the worst point .

Regards,
Tomas

 

[ereisch]

Hrm, that didn't work for me with the last model I tried it with. I must have done something different with the splines that the surface didn't like. Thanks for the help.

P.S. -- Is there any issue with having several dozen datum planes in a single part file? Is there a more efficient way of accomplishing this?

 

[JohnRBaker]

NO, Datum Planes are just like any other object. If you need a dozen to do the job, so be it. It would be like asking if I could have too many curves representing the contour of the site. If that's what it takes to define the shape needed, that's what it takes. Of course, it's probably a good idea to hide them when not being used since they do tend to clutter-up the display ;-)

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

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