3D Curved Surface Profile

Operator Function

Calculate geometric tolerance - Curved Surface Profile
As shown in the figure below, for the input theoretical cylinder points, connect them with the perpendicular foot on the axis, extend the reverse line to find the intersection with the actual cylinder, and take the distance from the intersection to the corresponding theoretical cylinder point as 𝑑1, 𝑑2, ..., 𝑑n. The surface profile is:
2 × 𝑚𝑎𝑥(𝑑1, 𝑑2, ..., 𝑑n)

Parameter Introduction

Input Parameters

Parameter	Range	Default Value	Description	Illustration
Input Image	0-31	0	The IM number for image input
3D Reference			You can select a reference via binding
X			X-coordinate value of the 3D reference parameter; can be set via binding to X
Y			Y-coordinate value of the 3D reference parameter; can be set via binding to Y
Z			Z-coordinate value of the 3D reference parameter; can be set via binding to Z
X-Axis Angle	-10000000000.000-10000000000.000		X-axis angle value of the 3D reference parameter; can be set via binding for X-Axis Angle
Y-axis angle	-10000000000.000-10000000000.000		3D reference parameter Y-axis angle value; can be set via binding Y-axis angle
Z-axis angle	-10000000000.000-10000000000.000		3D reference parameter Z-axis angle value; can be set via the Z-axis angle binding

Calculation Parameters

Parameter	Range	Default Value	Description	Illustration
Actual Cylinder	Cylinder	-	Actual cylinder bottom face, top face center and radius
Theoretical Cylinder Surface	json file	-	Sampling points on the theoretical cylinder surface
Fit Point Cloud	true/false	false	When enabled, the point cloud fitting function is used. The theoretical cylinder surface fits the selected point cloud as closely as possible
Use Region Parameters	true/false	false	Enable when fitting point cloud. When enabled, point cloud selection is activated; when disabled, the entire IM point cloud is selected
Region	2D Window/2D Circular Window/2D Polygon Window/Box/Cylindrical Box/Rotated Box/Point Set (binding only)	Box	Manually select the point cloud to be fitted
Theoretical Cylinder Fitting Method	Least Squares/RANSAC	Least Squares	Fit the cylinder according to the selected method
K-Nearest Neighbors	3-500	20	The number of surrounding points searched when calculating the normal of a point on the point cloud. If the search point count is too large, it will introduce other points far from the current point, leading to inaccurate estimation; if the value is too small, some neighboring points will be ignored, also affecting the accuracy of normal estimation.
Distance Threshold	0-10000	0.15	When the distance between a data point and the fitted model is less than this threshold, the data point is considered an inlier (i.e., a point that conforms to the model); otherwise, it is considered an outlier (i.e., a point that does not conform to the model)
Max Iterations	100-10000	500	Set the maximum number of iterations

Result Display

Parameter	Range	Default Value	Description	Illustration
Actual Fitted Cylinder	true/false	false	The input actual fitted cylinder. If enabled, displayed on IM
Theoretical Cylinder	true/false	false	The input theoretical cylinder. If enabled, displayed on IM
Theoretical Cylinder Surface Points and Intersections	true/false	false	Displays two sets of points: the input theoretical cylinder surface points and the intersections of the reverse extension of the line connecting the theoretical cylinder surface points with the perpendicular foot on the theoretical cylinder central axis and the actual cylinder surface. If enabled, displayed on IM
Central Axis Points and Theoretical Cylinder Surface Intersections	true/false	false	The intersections of the points on the central axis with the theoretical cylinder surface. If enabled, displayed on IM
Surface Profile	true/false	false	The output surface profile. If enabled, displayed on IM

Output Parameters

Name	Type	Range	Description
Result	bool	true/false	true for success false for failure
Warning	bool	true/false	true indicates a warning false indicates no warning
Message	string		Output success, error, or warning messages. Empty if no error or warning.
Time	float		Operator execution time, unit: ms
theoretical_cylinder	cylinder		Theoretical cylinder parameters
intersections	point3d[]		Intersections
profile_of_surface	float		Surface profile
result	string	OK/NG	Whether the surface profile is within range

Tip

For more detailed parameter type descriptions, please refer to Type Definition

Exception Troubleshooting

No.	Exception Information	Corresponding Parameter	Solution
1	Input point cloud has fewer than 6 points		Confirm whether the IM contains 6 valid points. If not, load a point cloud or switch to a compliant IM
2	Actual cylinder type is {0}, invalid input type	Cylinder Type	Check if the cylinder type is Cylinder
3	Parameter {0} cannot be empty	Path	Check if the path is empty
4	File {0} does not exist or cannot be accessed	Path	Check if the path is valid
5	Input theoretical cylinder fitting method is {0}, invalid fitting method	Fitting Method	Check if the fitting method is one of Least Squares/RANSAC
6	Input theoretical cylinder point cloud is empty		Check if the theoretical cylinder surface file is empty
7	Input profile range minimum is greater than maximum, invalid profile range		Set the profile range minimum to be less than or equal to the maximum
8	Input region type is {0}, invalid region type	Region Type	Check if the region type is one of 2D Window/2D Circular Window/2D Polygon Window/Box/Cylindrical Box/Rotated Box/Point Set
9	Input polygon has fewer than 3 vertices, cannot form a polygon		Add 2D polygon window vertices to make the number of vertices at least 3
10	Input region is empty		1. Check if the selection is empty 2. Check if the point set is empty

Example Introduction

Engineering Design

1. Select the Load Point Cloud tool to load the 3D point cloud to be processed into IM0;

2. Select the 3D Cylinder Fitting tool to fit the actual plane.

3. Select the 3D Curved Surface Profile tool.

Tool Usage

1. Select the input image to be operated on. The image number must match the IM number of the image in the project.

2. Do not enable region parameters, or enable region and select the region type as Box. Move the box to the position to be tested, surrounding the point cloud to be tested.

Usage Tips

1. Drag or scale the box through the ROI controller on the image window;
2. Directly modify the start or end coordinates of the box in the calculation parameters to adjust the box position and size

3. Set parameters

4. Check the desired display content in the result display section

5. Click Test to check if the image window and parameters meet expectations

6. If there are no issues, click Save. Run the operator in the run list to view the running results in the corresponding IM.