3D Arc Profile of a Line

Operator Function

Calculate the geometric tolerance - arc profile of a line
As shown in the figure below, connect the theoretical arc point with the theoretical circle center, take the reverse extension line and its intersection with the actual arc, compute the distance from the intersection point to the corresponding theoretical arc point, denoted as 𝑑1, 𝑑2, …, 𝑑n. The profile of a line is:
2 × 𝑚𝑎𝑥(𝑑1, 𝑑2, …, 𝑑n)

Parameters

Input Parameters

Parameter	Range	Default	Description	Diagram
Profile	-	-	Profile input
Profile Index	-	-	Index of the profile input

Calculation Parameters

Parameter	Range	Default	Description	Diagram
Actual Circle	1D Circle	-	Fitted circle of the actual profile
Theoretical Arc	json file	-	Points passed through by the theoretical arc
Theoretical Arc Plane	XY Plane / XZ Plane / YZ Plane	-	Measurement point file on the measured plane
Fit Point Cloud	true/false	false	Translate the theoretical position points to the position of the point cloud enclosed by the most-fitting region selection, so that the measurement value is minimized
Use Region Parameter	true/false	false	When enabled, use Region as input; when disabled, use Input Image as input
Region	1D Window	1D Window	Manually select a suitable ROI region You can select an existing ROI region by binding
Theoretical Circle Fitting Method	Least Squares / RANSAC	Least Squares	Select the method for fitting the circle
Distance Threshold	0.0-50.0	0.02	Select an appropriate distance threshold; increase this parameter when there is more noise, decrease it when there is less noise
Maximum Iterations	100-10000	1000	Set the maximum number of iterations

Result Display

Parameter	Range	Default	Description	Diagram
Actual Fitted Circle	true/false	false	The input actual fitted circle; when enabled, displayed on the IM
Theoretical Circle	true/false	false	The input theoretical circle; when enabled, displayed on the IM
Theoretical Arc Points and Intersection Points	true/false	false	Display two sets of points: the input theoretical arc points and the intersection points of the reverse extension line of the line connecting the theoretical arc points with the circle center and the actual arc; when enabled, displayed on the IM
Lines Connecting Arc Points	true/false	false	Lines connecting the arc points and the actual points; when enabled, displayed on the IM
Arc Profile of a Line	true/false	false	The output perpendicularity; when enabled, displayed on the 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 none
Message	string		Output success, error, or warning message; empty if no error or warning
Time	float		Operator execution time, unit: ms
center_distance	float		Center distance
profile_of_line	float		Profile of a line
result	string	OK/NG	Whether the profile of a line is within range

Tip

For more details on parameter types, please refer to Type Definition

Troubleshooting

No.	Exception Message	Corresponding Parameter	Solution
1	The number of input profile points is less than 3		Confirm whether the IM contains valid points. If there are fewer than three valid points, load the point cloud or switch to an IM with valid points
2	RANSAC circle fitting failed	Circle Type	Increase the distance threshold
3	The type of the actual circle is {0}, an incorrect input type		Check whether the actual circle type is a 1D Circle
4	Parameter {0} cannot be empty	Path	Check whether the path is empty
5	File {0} does not exist or cannot be accessed	Path	Check whether the path is valid
7	The input theoretical position point cloud is empty		Check whether the theoretical position point json file is empty
8	The type of the input datum line is {0}, an invalid datum line type	Datum Line Type	Check whether the datum line type is a 3D Line

Examples

Engineering Setup

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

2. Select the 3D Profile Extraction tool to fit the actual plane;

3. Select the 3D Profile Circle tool to fit the datum plane;

4. Select the 3D Arc Profile of a Line tool.

Tool Usage

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

2. Either disable the use-region parameter, or enable the region and select the region type as Box, then move the box to the position to be measured so that it encloses the point cloud to be measured.

Usage Tips

1. Drag or scale the box via 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 the parameters.

4. Check the items to be displayed in the Result Display panel.

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

6. After confirming there are no problems, click Save, then run the operator in the run list to view the running result in the corresponding IM.