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IDProjectCategoryView StatusLast Update
0004750ExpressionsBugpublic2021-09-25 00:22
Reportergbroques Assigned To 
PrioritynormalSeverityminorReproducibilityalways
Status newResolutionopen 
Summary0004750: "Invalid property owner" for Visibility Expression of Link Array
DescriptionI'm trying to bind an expression to the Visibility property of a link array created with the Draft workbench from a spreadsheet.

However, I see this error in the Report View:
17:44:57 <Exception> Invalid property owner.

It seems like I see this error no matter what the Visibility property expression of the Link Array references.

For example, referencing itself (e.g. Count or .NumberX) or referencing some property of the underlying linked object (e.g. Cube.Length).

Essentially, what I want to do is toggle the Visibility to False when the Count is 0.

Since Link Arrays still show the object when the count is 0 (e.g. Number X, Y, and Z are 0 for an Ortho array still shows 1 object).

In my case, the number of objects in the the array is dynamic and based on an expression.

"Invalid property owner" Error in FreeCAD Soure Code:
https://github.com/FreeCAD/FreeCAD/blob/0.19.2/src/App/PropertyExpressionEngine.cpp#L547-L549
Steps To ReproduceSteps to Reproduce

  1. Create new document
  2. Create spreadsheet from Spreadheet workbench
  3. Add expression like =5 > 1 ? True : False with an alias of CubeArrayVisibility to newly created spreadsheet
  4. Create Cube from Part workbench
  5. Create Link Array (ortho) from Draft workbench using Cube
  6. Select Link Array from Tree View
  7. Right click data tab in combo view, Select "Show All".
  8. Right click Visibility property. Select Expression
  9. Bind the CubeArrayVisibility to the Visbility property of the Array
Additional InformationFreeCAD Forum Post
https://forum.freecadweb.org/viewtopic.php?f=3&t=62468
Tagsarray, expressions, python feature
FreeCAD Information

OS: Ubuntu 20.04.3 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 0.19.2)
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.8
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

Activities

gbroques

2021-09-25 00:22

reporter   ~0015953

See attached LinkArrayVisibilityIssue.FCStd.

Issue History

Date Modified Username Field Change
2021-09-24 00:26 gbroques New Issue
2021-09-24 00:28 gbroques Description Updated
2021-09-24 00:28 gbroques Steps to Reproduce Updated
2021-09-24 00:30 gbroques Description Updated
2021-09-24 00:30 gbroques Steps to Reproduce Updated
2021-09-24 00:30 gbroques Description Updated
2021-09-24 00:32 gbroques Additional Information Updated
2021-09-24 01:19 gbroques Tag Attached: expressions
2021-09-24 01:19 gbroques Tag Attached: array
2021-09-24 01:20 gbroques Tag Attached: python feature
2021-09-25 00:22 gbroques Note Added: 0015953
2021-09-25 00:22 gbroques File Added: LinkArrayVisibilityIssue.FCStd