How Do You Deal with Non-CAD Reference Data?

MLombard
Retired

3d-foot-scan.jpgSome people get all the luck. They always know someone at the front of the line, or they are always in the right place at the right time, or maybe they live somewhere where it never snows, never get hit by hurricanes or earthquakes, and they always get enough but not too much rain. Luck with the weather is on a lot of people's mind here in the US anyway.

 

And so it goes in the CAD world too. Some people get all the luck. Everything they design is built cleanly from scratch. But you ( and I) don't have that kind of luck. We always have to work from some reference. Maybe the reference is laser scanned in, and we have to make a solid or surface out of it in some way. Or maybe all we have to work with are pictures, and you have to fit actual 3D parts around 2D images and the 3D you can derive from that rough reference.

 

Or maybe you were a really bad person in a past life, and your CAD data works around parts that can't really be represented nicely in CAD. Say you make agricultural equipment, and you want to represent hay or corn or a cow. If you were really bad, you might have to work around mesh data like models from 3DSmax or Zbrush. These models can be beautiful and extremely detailed in their native format, but when you bring mesh data into a CAD package, it is difficult to work with, bogs down the graphics, and makes life miserable.

 

Part of the problem is that the mesh data is everywhere. There are 3Dsmax models of just about anything you can imagine, and a lot of that can be reused as reference in engineering work. With the rise of 3d printing, 3d scanning is also becoming more popular, and CAD software really should be able to deal with this kind of data.

 

How do Solid Edge users handle this kind of challenge? While we do have an advantage in imported NURBS type data over many other traditional CAD packages, working with "less evolved" data actually slows us down. How do you work with non-CAD reference data, and what difficulties do you run into along the way?

Comments
Valued Contributor
Problems for sure. I recently downloaded a file from a company representing one of those camera setups for reverse engineering. It was a big file and so inaccurate that I was amazed. You could not even determine an accurate centerline on a bore as there were about five different radiuses in this lopsided thing. Not one flat surface on there and the best possible result would have been purely guess work as to what the real sizes of the part were. Perhaps the bigger question is how do you even get good data before you even think about working on your data.
PLM World Member Valued Contributor PLM World Member Valued Contributor
PLM World Member Valued Contributor

I an past job everything started with a scan. Then it went through Raindrop or Imageware to make surfaces that were imported into CAD. The problem at the time was that these surfaces were not parametric and we found them difficult to edit. Does ST eliminate that problem by letting you edit those NURBS surfaces?

 

Is the picture a CT scan of a real foot?

Retired

Dave,

 

Good data is usually a combination of good hardware, good software and good technique. You might get by with only 2 of the 3, but it's tough. There's a lot of crappy scan data out there for various reasons. I've got a cheap scanner with terrible software. So whenever I get bad data, I know whose fault it is (mine).

 

I think as this market increases, the hardware and software will get better, so the data may get better as well.

 

HS

 

When people talk about Raindrop, I get very jealous. I really wish I could use that stuff. It's magic, or next best thing. Kinda pricy too, but if you do a lot of scanning, the price is easy to justify, especially when you look at the alternatives.

 

If Raindrop gives you stuff like planar and cylindrical surfaces, then yes, Synchronous can edit those. I'll bet you can set up that software to give you good results like that.

Community Manager

@HS. It's not sync per set that will let you edit imported bsplines, but with ST6 we introduced Redefine Surface. This allows you to substitute an editable surface for an uneditable one. It works pretty well. You should give it a whirl if this is an area you do much of.

 

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