Best way to apprach my procedure to create an accurate surface


(Engineering) #1

Hello, I am very new to Rhino and I am looking to hopefully find the best way to approach a simple task. I have coordinate data (x,y,c) from a coordinate measuring machine (4262 points) that I am trying to create an accurate surface (face of an injection molded part) that I can bring into SolidWorks to create a solid model to represent geometry that I can machine. The maximum (z axis) variation of my measured geometry is .005" so I would like a to have a very accurate surface. Is importing my xyz values into a point could, then using the patch command the best way?

(David Cockey) #2

I would use Patch, probably with a starting surface. If the surface has four “sides” then the starting surface may be straightforward. If not then my strategy for the starting surface would depend on the shape of the object. The points can be easily imported using a .txt or .csv file as x,y,z triplets.

Experiment with the number of control points and degree of the starting surface until you have a satisfactory result. Tradeoffs may be between conformance to the points, smoothness, and “oscillations”.

(Engineering) #3

Thanks for the reply, My points are of one fairly flat face approximately 3" in diameter and vary in the z direction by .005" at max.(essentially the flatness of a part) When using the patch command is it better to have a lower or higher stiffness level, and lower / higher U,V spams?

(David Cockey) #4

If the points are well distributed with no large gaps then a lower stiffness value is generally better. Number of U, V spans is best determined by experimenting.