How to get rows of 3D data points of a 3D model (like toy-car) for B-spline surface?

I want sample data points of a 3D model like toy-car or spade as rows of 3D data points to generate a interpolating B-spline surface.

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4 Answers

I'd take the sample points whether as a cloud or as a mesh and import them to Design X, or another program like it.
You'll be able to then generate cutting planes, and extract the profiles of the data from each plane/section.

Obviously the quality will be dependent on the quality of the original data. I also doubt you'd be able to use the sections directly. It usually works best to use the sections as a guide, then create new sketches with better curvature and control points.

 
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I think you have four options, but other members might have some other ideas:

1. Make use of a laser, or visible light scanning system. Just make sure the scanner is suited to the model/feature size you'll be trying to capture.

2. Make use of CMM equipment These machines will probe the surface of an object and provide a data set of points.

3. Likely too advanced for this project, but CT scans of an item can be created. The resulting data can then be processed to give profiles/points at different layers.

4. The object can be physically sliced, ground, milled, or otherwise destroyed in a deliberate fashion. Data can be captured for each step of the process with photos, flatbed scanner, or simply tracing or stamping.

 
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Software typically costs money as well.
Have you considered using photographs? With enough photos, you can use software to recreate 3D object in digital format.
More software will allow you to slice the data.

You will still need a physical camera to get the initial input for the software.
Check out this tutorial which includes a link with more details: Amazing Realistic Rendering with Reality Capture from Photographs

 
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If you are able to get it to a mesh type format like STL, the free MeshLab should be able to convert it to an x,y,z point cloud.

For example the simple STL file 9:4:1 Monolith converts with meshlab to the XYZ point cloud:
0.000000 0.000000 304.799988 -1.570796 -0.000000 0.000000
0.000000 0.000000 0.000000 -0.110657 -0.000000 0.000000
0.000000 2743.199951 0.000000 -1.570796 -0.000000 0.000000
1219.199951 2743.199951 0.000000 1.460139 0.000000 0.000000
1219.199951 0.000000 304.799988 1.460139 0.000000 0.000000
0.000000 2743.199951 304.799988 0.000000 1.570796 0.000000
0.000000 2743.199951 0.000000 0.000000 0.244979 0.000000
1219.199951 2743.199951 304.799988 0.000000 0.000000 1.152572
1219.199951 0.000000 0.000000 0.000000 0.000000 -1.152572
0.000000 0.000000 0.000000 0.000000 0.000000 -1.570796

 
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