Using facet feature as a reference

[ptc-6710258]

Hey all, I am new here and just got my hands on Creo 3.0.

I have worked on SolidWorks over the period of 4 years so I know a few things about CAD.

What pushed me to start exploring creo was that I'm starting to have the need to work on laser scanned files, STL, VRML, IGES and SolidWorks has proven to be a real pain in the ass in creating or even worse, recreating weird surfaces. As far as it seems, creo isn't.

My question is simple - is there any way I can attach geometry to a facet feature obtained from STL o VRML files? I know I can edit, delete and refine it, but I have no clue how to sketch splines on it (or at least share sketch points with it). If it is possible, it would be nice if someone could at least point me into the right direction.

I have heard that reverse engineering extension does just this, but please note that I do not have any more spare money to throw away for extensions. It would be different if there was a way to try a free trial of this extension. Also my file has a few holes that are not small, so I doubt automatic surface creation would do any good, I plan on going manual in stead, so please.

Thank you for your time.

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[gkoch]

Hello Karlis,

welcome to the forum!

I have not much practical experience with scanned data in production, but from the functionality point of view, the key points are:

Triangulated surfaces and analytic/spline surfaces (as used for Creo model geometry) are not compatible.

A high number of small triangles still does not make a smooth surface like a cylindrical or ball shaped surface.

You cannot use facetted geometry to sketch on, make it solid or intersect it with the solid geometry.

So what is the use of it?

1. On one hand it is a very light to handle representation of geometry (as there is no "intelligence" in it and plane triangles are simple to be displayed). Therefore it can be used as a placeholder for surrounding environment spending few resources (actually Creo itself is using so-called shrinkwrap representations of components, which can be triangulated surfaces, as kind of mockups to speed up performance in assemblies - of course you use shrinkwrap only for those components you do not work with)
2. If you want to create model geometry out of triangulated imports, you need to rebuild the geometry based on the triangulated surfaces. There are basically two methods:
   • You can create high quality suraces by projecting curves onto the triangulated surfaces and then create surfaces out of the curves. This is basically what the restyle functionality offers tools for.
   • You can keep the triangle shapes and create a faceted solid by saving models containing facetted geometry with the file type Shrinkwrap using the option "Faceted Solid". Make sure to turn the quality high enough to get acceptable quality (you may follow the warning and rather start with low quality and increase it slowly, as the creation time is exponential). The resulting model will still have the "scaled" look, but its actually a solid that you can cut or merge with other solid geometry.

Do we have some users on this thread with practical experience using those methods in production?