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PC_143651128-Gravel
8-Gravel
December 18, 2025
Question

Reverse engineering -skeleton of complex geometry

  • December 18, 2025
  • 2 replies
  • 278 views

Hello,

 

I have partial 3D scan (.stl) of impeller that needs to be converted to CAD model. I cut the model horizontally by stacking planes on top of eachother so I got intersection lines. I did the same with vertical planes, all going through axis Z (axis of rotation). I did that in different program and imported the resulting curves to Creo (.stp). 

I wonder what would be most efficient way to fill the surfaces. Problems I have are: lines are not as one, but instead there are many of them which is a problem for boundary blend. Of course I would have to firstly fill the missing lines where 3D scan is missing. Anybody has experience with this: either via .stl or .stp imported to creo10? 

 

Thank you for suggestions!

2 replies

K
KenFarley21-Topaz II
21-Topaz II
December 18, 2025

I've had to do this kind of thing in the past, trying to use an STL file to create a model. I didn't use the STL directly for anything. An STL is just a huge set of planar facets. Any "curve" obtained from it is not a mathematical curve, it's a bunch of tiny line segments.

What I ended up doing is modeling the object in question directly, using measurements from the STL. Using sets of points to find radii, lengths, etc. I assemble my nice geometrically "clean" model with the STL model and check that I'm getting things right.

The model you are attempting to build seems like more or less a simple revolved solid, except for the spiral(?) passage. If it was me I'd probably take the approach of building the main outer body, then attack that spiral passage maybe with equation driven curves. That way you'll be able to get the geometry to be more rigorously defined, and it will allow you to, if you wish, make variations, make a larger version, etc.

    M
    matthewholter5-Regular Member
    5-Regular Member
    December 20, 2025

    Ther are many tactics to "trace" facet data. The reverse engineering module/restyle" (if that is till what is called) is the best option to genrate the surface patches. After I have traced the key locations with the curve pace on the facet data, I collapse to independent geometry and remove the facet data . If appropriate for the project, I begin building parametric surfaces; and compare them back to the facet data before removing it from the model tree

    The freestyle and style tools are aslo helpful for "tracing" facet data if you dont have acess to restyle.

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