Creating a cylinder from points

Greetings all! I’ve recently acquired a Romer Cimcore 3000i (winrds) & would like to become more proficient at using this digitizer for reverse engineering. That being said, is there a way to digitize a cylinder using points? I’d hoped to be able to measure some tubing weldments by picking points on the straight portions, but I’ve yet to stumble upon an easy way to define the centerline & diameter.

Any assistance would be greatly appreciated!

I had to find the centre of a mesh tube the othere day,
My strategy was to make a few sections, flattening them (ProjectToCplane) and running AreaCentroid to find the average center…

Hi - If you only have a few points and not an entire mesh, you could just run the Cylinder command, hit the FitPoints option and then select all your points.
-wim

Thanks for the input! I had another chance to play recently & I’ve attempted to attach the (unsatisfactory) result.

I’m new to rhino, so i’m sure its a case of attempting to run before I can crawl.

To obtain what I have, I taped a piece of graph paper to the tube & attempted to pick the intersections of the grid rather than just picking points at random.

Cairn. I’ve yet to attempt your suggestion, but hope to give it a try soon.

basically, I was hoping to easily obtain the centerline of multiple tubes to extract data regarding their relationships to one another.

Thanks again!

tube test.3dm (49.3 KB)

Ah, I reaslise you have a point cloud from the scan right?
The FitPoints option in the Cylinder command expects a set of points forming the base circle of the cylinder, so dificult to orient. Hard to tell, but if I were you, I would try and build new cylinders in Rhino and then scale/move/rotate them to coincide with your points as best as you can, then measure the Rhino geometry…

Thanks again for the feedback! while playing with your suggestion, I thought I may be able to clamp a vee-block to the tube(s) in question, thus creating a possible perpendicular plane to create & project the points onto. More to follow!

Hi @EW57,

Assuming you have straight tubes I’d suggest measuring the tube diameter(s) with a vernier or micrometer. That will give a more accurate result than scanning. You can use the dimension(s) to create cylinders in Rhino which, as @cairn suggests, you can orient to your point clouds. Reducing the number of variables in this way makes the fitting simpler.

Regards
Jeremy