Use First Point and Blue Construction Geometry Vector

Oct 13, 2025 by talynt.org 79 views

Problem Description

When using the Move/Array transform (W) in Sketcher, the resulting sketch has many new DoF (degrees of freedom) namely both x- and y-coordinates for all new copies. This can be frustrating, especially when trying to create precise and accurate designs. To address this issue, it would be very helpful to automatically add point-coincident-constraints from the original to the copies.

Two Cases

There are two cases to consider when dealing with the Move/Array transform:

Case A: Both Start and Endpoints Belong to the Selected Set of Elements

In this case, the two or three points are used for the coincidences between parent and child. This means that the original and copied elements will share the same coordinates, ensuring that the design remains accurate and precise.

Case B: Otherwise

If the start and endpoints do not belong to the selected set of elements, the set of elements has a "first" point. This point should be used together with a blue construction geometry vector to fix the children. This approach ensures that the copied elements are properly constrained and aligned with the original element.

Full Version Info

The following information provides details about the system configuration and version:

OS: Arch Linux (KDE/plasmax11/xcb)
Architecture: x86_64
Version: 1.0.0.39109 (Git)
Build type: Release
Branch: makepkg
Hash: 2fcc5317fe3aee96ca73475986a577719fc78e20
Python: 3.13.2
Qt: 6.8.2
Coin: 4.0.3
Vtk: 9.4.1
OCC: 7.8.1
Locale: English/United States (en_US)
Stylesheet/Theme/QtStyle: unset/FreeCAD Classic/oxygen
Installed mods:
- fasteners: 0.5.24
- ThreadProfile: 1.90.0
- 3D_Printing_Tools

Subproject(s) Affected

None of the subprojects are affected by this issue.

Anything Else?

It's worth noting that this suggestion was previously the default in some former versions of FreeCAD. This suggests that the feature was removed or changed at some point, leading to the current behavior.

Side-Note

A minor issue worth mentioning is the inconsistent counting of columns and rows in the Move/Array transform. The number of columns is 0-based, counting the number of additional elements, while the number of rows is 1-based, counting the total number of rows. This can be confusing and may lead to errors.

Code of Conduct

The author agrees to follow this project's Code of Conduct.

Solution

To address the issue of sketcher translate producing many new DOF, the following solution can be implemented:

Automate Point-Coincident-Constraints: Automatically add point-coincident-constraints from the original to the copies. This can be achieved by modifying the Move/Array transform to include the necessary constraints.
Use First Point and Blue Construction Geometry Vector: In case B, use the first point of the set of elements together with a blue construction geometry vector to fix the children. This ensures that the copied elements are properly constrained and aligned with the original element.

Q: What is the issue with the Move/Array transform in Sketcher?

A: The Move/Array transform in Sketcher produces many new DoF (degrees of freedom) namely both x- and y-coordinates for all new copies. This can be frustrating, especially when trying to create precise and accurate designs.

Q: Why is it necessary to add point-coincident-constraints from the original to the copies?

A: Adding point-coincident-constraints from the original to the copies ensures that the design remains accurate and precise. This is especially important when working with complex designs that require precise alignment and positioning.

Q: What are the two cases to consider when dealing with the Move/Array transform?

A: There are two cases to consider:

Case A: Both start and endpoints belong to the selected set of elements. In this case, the two or three points are used for the coincidences between parent and child.
Case B: Otherwise, the set of elements has a "first" point. This point should be used together with a blue construction geometry vector to fix the children.

Q: Why is the counting of columns and rows in the Move/Array transform inconsistent?

A: The counting of columns and rows in the Move/Array transform is inconsistent because the number of columns is 0-based, counting the number of additional elements, while the number of rows is 1-based, counting the total number of rows. This can be confusing and may lead to errors.

Q: Was this feature previously the default in some former versions of FreeCAD?

A: Yes, this feature was previously the default in some former versions of FreeCAD. This suggests that the feature was removed or changed at some point, leading to the current behavior.

Q: How can I implement the solution to address the issue of sketcher translate producing many new DOF?

A: To address the issue of sketcher translate producing many new DOF, you can implement the following solution:

Automate Point-Coincident-Constraints: Automatically add point-coincident-constraints from the original to the copies. This can be achieved by modifying the Move/Array transform to include the necessary constraints.
Use First Point and Blue Construction Geometry Vector: In case B, use the first point of the set of elements together with a blue construction geometry vector to fix the children. This ensures that the copied elements are properly constrained and aligned with the original element.

Q: What are the benefits of implementing the solution to address the issue of sketcher translate producing many new DOF?

A: The benefits of implementing the solution to address the issue of sketcher translate producing many new DOF include:

Improved accuracy and precision: The solution ensures that the design remains accurate and precise, reducing the number of new DOF and making it easier to work with.
Increased productivity: By automating the process of adding point-coincident-constraints and using the first point and blue construction geometry vector, you can save time and increase productivity.
Better design outcomes: The solution ensures that the design is properly constrained and aligned, leading to better design outcomes and reduced errors.

Q: How can I get involved in the development of FreeCAD and contribute to the solution?

A: You can get involved in the development of FreeCAD and contribute to the solution by:

Reporting bugs and issues: Report any bugs or issues you encounter while using FreeCAD, including the issue of sketcher translate producing many new DOF.
Contributing code: Contribute code to the FreeCAD project, including modifications to the Move/Array transform to include the necessary constraints.
Participating in discussions: Participate in discussions with the FreeCAD community, including forums and mailing lists, to share your ideas and feedback on the solution.